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-rw-r--r--arch/riscv/lib/Makefile13
-rw-r--r--arch/riscv/lib/clear_page.S74
-rw-r--r--arch/riscv/lib/delay.c111
-rw-r--r--arch/riscv/lib/error-inject.c10
-rw-r--r--arch/riscv/lib/memcpy.S110
-rw-r--r--arch/riscv/lib/memmove.S318
-rw-r--r--arch/riscv/lib/memset.S113
-rw-r--r--arch/riscv/lib/strcmp.S122
-rw-r--r--arch/riscv/lib/strlen.S133
-rw-r--r--arch/riscv/lib/strncmp.S138
-rw-r--r--arch/riscv/lib/tishift.S76
-rw-r--r--arch/riscv/lib/uaccess.S237
12 files changed, 1455 insertions, 0 deletions
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
new file mode 100644
index 0000000000..26cb2502ec
--- /dev/null
+++ b/arch/riscv/lib/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+lib-y += delay.o
+lib-y += memcpy.o
+lib-y += memset.o
+lib-y += memmove.o
+lib-y += strcmp.o
+lib-y += strlen.o
+lib-y += strncmp.o
+lib-$(CONFIG_MMU) += uaccess.o
+lib-$(CONFIG_64BIT) += tishift.o
+lib-$(CONFIG_RISCV_ISA_ZICBOZ) += clear_page.o
+
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/riscv/lib/clear_page.S b/arch/riscv/lib/clear_page.S
new file mode 100644
index 0000000000..d7a256eb53
--- /dev/null
+++ b/arch/riscv/lib/clear_page.S
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/alternative-macros.h>
+#include <asm-generic/export.h>
+#include <asm/hwcap.h>
+#include <asm/insn-def.h>
+#include <asm/page.h>
+
+#define CBOZ_ALT(order, old, new) \
+ ALTERNATIVE(old, new, 0, \
+ ((order) << 16) | RISCV_ISA_EXT_ZICBOZ, \
+ CONFIG_RISCV_ISA_ZICBOZ)
+
+/* void clear_page(void *page) */
+SYM_FUNC_START(clear_page)
+ li a2, PAGE_SIZE
+
+ /*
+ * If Zicboz isn't present, or somehow has a block
+ * size larger than 4K, then fallback to memset.
+ */
+ CBOZ_ALT(12, "j .Lno_zicboz", "nop")
+
+ lw a1, riscv_cboz_block_size
+ add a2, a0, a2
+.Lzero_loop:
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBOZ_ALT(11, "bltu a0, a2, .Lzero_loop; ret", "nop; nop")
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBOZ_ALT(10, "bltu a0, a2, .Lzero_loop; ret", "nop; nop")
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBOZ_ALT(9, "bltu a0, a2, .Lzero_loop; ret", "nop; nop")
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBOZ_ALT(8, "bltu a0, a2, .Lzero_loop; ret", "nop; nop")
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ CBO_zero(a0)
+ add a0, a0, a1
+ bltu a0, a2, .Lzero_loop
+ ret
+.Lno_zicboz:
+ li a1, 0
+ tail __memset
+SYM_FUNC_END(clear_page)
+EXPORT_SYMBOL(clear_page)
diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c
new file mode 100644
index 0000000000..49d510ba75
--- /dev/null
+++ b/arch/riscv/lib/delay.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ */
+
+#include <linux/delay.h>
+#include <linux/math.h>
+#include <linux/param.h>
+#include <linux/timex.h>
+#include <linux/types.h>
+#include <linux/export.h>
+
+#include <asm/processor.h>
+
+/*
+ * This is copies from arch/arm/include/asm/delay.h
+ *
+ * Loop (or tick) based delay:
+ *
+ * loops = loops_per_jiffy * jiffies_per_sec * delay_us / us_per_sec
+ *
+ * where:
+ *
+ * jiffies_per_sec = HZ
+ * us_per_sec = 1000000
+ *
+ * Therefore the constant part is HZ / 1000000 which is a small
+ * fractional number. To make this usable with integer math, we
+ * scale up this constant by 2^31, perform the actual multiplication,
+ * and scale the result back down by 2^31 with a simple shift:
+ *
+ * loops = (loops_per_jiffy * delay_us * UDELAY_MULT) >> 31
+ *
+ * where:
+ *
+ * UDELAY_MULT = 2^31 * HZ / 1000000
+ * = (2^31 / 1000000) * HZ
+ * = 2147.483648 * HZ
+ * = 2147 * HZ + 483648 * HZ / 1000000
+ *
+ * 31 is the biggest scale shift value that won't overflow 32 bits for
+ * delay_us * UDELAY_MULT assuming HZ <= 1000 and delay_us <= 2000.
+ */
+#define MAX_UDELAY_US 2000
+#define MAX_UDELAY_HZ 1000
+#define UDELAY_MULT (2147UL * HZ + 483648UL * HZ / 1000000UL)
+#define UDELAY_SHIFT 31
+
+#if HZ > MAX_UDELAY_HZ
+#error "HZ > MAX_UDELAY_HZ"
+#endif
+
+/*
+ * RISC-V supports both UDELAY and NDELAY. This is largely the same as above,
+ * but with different constants. I added 10 bits to the shift to get this, but
+ * the result is that I need a 64-bit multiply, which is slow on 32-bit
+ * platforms.
+ *
+ * NDELAY_MULT = 2^41 * HZ / 1000000000
+ * = (2^41 / 1000000000) * HZ
+ * = 2199.02325555 * HZ
+ * = 2199 * HZ + 23255550 * HZ / 1000000000
+ *
+ * The maximum here is to avoid 64-bit overflow, but it isn't checked as it
+ * won't happen.
+ */
+#define MAX_NDELAY_NS (1ULL << 42)
+#define MAX_NDELAY_HZ MAX_UDELAY_HZ
+#define NDELAY_MULT ((unsigned long long)(2199ULL * HZ + 23255550ULL * HZ / 1000000000ULL))
+#define NDELAY_SHIFT 41
+
+#if HZ > MAX_NDELAY_HZ
+#error "HZ > MAX_NDELAY_HZ"
+#endif
+
+void __delay(unsigned long cycles)
+{
+ u64 t0 = get_cycles();
+
+ while ((unsigned long)(get_cycles() - t0) < cycles)
+ cpu_relax();
+}
+EXPORT_SYMBOL(__delay);
+
+void udelay(unsigned long usecs)
+{
+ u64 ucycles = (u64)usecs * lpj_fine * UDELAY_MULT;
+ u64 n;
+
+ if (unlikely(usecs > MAX_UDELAY_US)) {
+ n = (u64)usecs * riscv_timebase;
+ do_div(n, 1000000);
+
+ __delay(n);
+ return;
+ }
+
+ __delay(ucycles >> UDELAY_SHIFT);
+}
+EXPORT_SYMBOL(udelay);
+
+void ndelay(unsigned long nsecs)
+{
+ /*
+ * This doesn't bother checking for overflow, as it won't happen (it's
+ * an hour) of delay.
+ */
+ unsigned long long ncycles = nsecs * lpj_fine * NDELAY_MULT;
+ __delay(ncycles >> NDELAY_SHIFT);
+}
+EXPORT_SYMBOL(ndelay);
diff --git a/arch/riscv/lib/error-inject.c b/arch/riscv/lib/error-inject.c
new file mode 100644
index 0000000000..d667ade2bc
--- /dev/null
+++ b/arch/riscv/lib/error-inject.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+void override_function_with_return(struct pt_regs *regs)
+{
+ instruction_pointer_set(regs, regs->ra);
+}
+NOKPROBE_SYMBOL(override_function_with_return);
diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
new file mode 100644
index 0000000000..1a40d01a95
--- /dev/null
+++ b/arch/riscv/lib/memcpy.S
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2013 Regents of the University of California
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+/* void *memcpy(void *, const void *, size_t) */
+ENTRY(__memcpy)
+WEAK(memcpy)
+ move t6, a0 /* Preserve return value */
+
+ /* Defer to byte-oriented copy for small sizes */
+ sltiu a3, a2, 128
+ bnez a3, 4f
+ /* Use word-oriented copy only if low-order bits match */
+ andi a3, t6, SZREG-1
+ andi a4, a1, SZREG-1
+ bne a3, a4, 4f
+
+ beqz a3, 2f /* Skip if already aligned */
+ /*
+ * Round to nearest double word-aligned address
+ * greater than or equal to start address
+ */
+ andi a3, a1, ~(SZREG-1)
+ addi a3, a3, SZREG
+ /* Handle initial misalignment */
+ sub a4, a3, a1
+1:
+ lb a5, 0(a1)
+ addi a1, a1, 1
+ sb a5, 0(t6)
+ addi t6, t6, 1
+ bltu a1, a3, 1b
+ sub a2, a2, a4 /* Update count */
+
+2:
+ andi a4, a2, ~((16*SZREG)-1)
+ beqz a4, 4f
+ add a3, a1, a4
+3:
+ REG_L a4, 0(a1)
+ REG_L a5, SZREG(a1)
+ REG_L a6, 2*SZREG(a1)
+ REG_L a7, 3*SZREG(a1)
+ REG_L t0, 4*SZREG(a1)
+ REG_L t1, 5*SZREG(a1)
+ REG_L t2, 6*SZREG(a1)
+ REG_L t3, 7*SZREG(a1)
+ REG_L t4, 8*SZREG(a1)
+ REG_L t5, 9*SZREG(a1)
+ REG_S a4, 0(t6)
+ REG_S a5, SZREG(t6)
+ REG_S a6, 2*SZREG(t6)
+ REG_S a7, 3*SZREG(t6)
+ REG_S t0, 4*SZREG(t6)
+ REG_S t1, 5*SZREG(t6)
+ REG_S t2, 6*SZREG(t6)
+ REG_S t3, 7*SZREG(t6)
+ REG_S t4, 8*SZREG(t6)
+ REG_S t5, 9*SZREG(t6)
+ REG_L a4, 10*SZREG(a1)
+ REG_L a5, 11*SZREG(a1)
+ REG_L a6, 12*SZREG(a1)
+ REG_L a7, 13*SZREG(a1)
+ REG_L t0, 14*SZREG(a1)
+ REG_L t1, 15*SZREG(a1)
+ addi a1, a1, 16*SZREG
+ REG_S a4, 10*SZREG(t6)
+ REG_S a5, 11*SZREG(t6)
+ REG_S a6, 12*SZREG(t6)
+ REG_S a7, 13*SZREG(t6)
+ REG_S t0, 14*SZREG(t6)
+ REG_S t1, 15*SZREG(t6)
+ addi t6, t6, 16*SZREG
+ bltu a1, a3, 3b
+ andi a2, a2, (16*SZREG)-1 /* Update count */
+
+4:
+ /* Handle trailing misalignment */
+ beqz a2, 6f
+ add a3, a1, a2
+
+ /* Use word-oriented copy if co-aligned to word boundary */
+ or a5, a1, t6
+ or a5, a5, a3
+ andi a5, a5, 3
+ bnez a5, 5f
+7:
+ lw a4, 0(a1)
+ addi a1, a1, 4
+ sw a4, 0(t6)
+ addi t6, t6, 4
+ bltu a1, a3, 7b
+
+ ret
+
+5:
+ lb a4, 0(a1)
+ addi a1, a1, 1
+ sb a4, 0(t6)
+ addi t6, t6, 1
+ bltu a1, a3, 5b
+6:
+ ret
+END(__memcpy)
+SYM_FUNC_ALIAS(__pi_memcpy, __memcpy)
+SYM_FUNC_ALIAS(__pi___memcpy, __memcpy)
diff --git a/arch/riscv/lib/memmove.S b/arch/riscv/lib/memmove.S
new file mode 100644
index 0000000000..838ff2022f
--- /dev/null
+++ b/arch/riscv/lib/memmove.S
@@ -0,0 +1,318 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2022 Michael T. Kloos <michael@michaelkloos.com>
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+SYM_FUNC_START(__memmove)
+SYM_FUNC_START_WEAK(memmove)
+ /*
+ * Returns
+ * a0 - dest
+ *
+ * Parameters
+ * a0 - Inclusive first byte of dest
+ * a1 - Inclusive first byte of src
+ * a2 - Length of copy n
+ *
+ * Because the return matches the parameter register a0,
+ * we will not clobber or modify that register.
+ *
+ * Note: This currently only works on little-endian.
+ * To port to big-endian, reverse the direction of shifts
+ * in the 2 misaligned fixup copy loops.
+ */
+
+ /* Return if nothing to do */
+ beq a0, a1, return_from_memmove
+ beqz a2, return_from_memmove
+
+ /*
+ * Register Uses
+ * Forward Copy: a1 - Index counter of src
+ * Reverse Copy: a4 - Index counter of src
+ * Forward Copy: t3 - Index counter of dest
+ * Reverse Copy: t4 - Index counter of dest
+ * Both Copy Modes: t5 - Inclusive first multibyte/aligned of dest
+ * Both Copy Modes: t6 - Non-Inclusive last multibyte/aligned of dest
+ * Both Copy Modes: t0 - Link / Temporary for load-store
+ * Both Copy Modes: t1 - Temporary for load-store
+ * Both Copy Modes: t2 - Temporary for load-store
+ * Both Copy Modes: a5 - dest to src alignment offset
+ * Both Copy Modes: a6 - Shift ammount
+ * Both Copy Modes: a7 - Inverse Shift ammount
+ * Both Copy Modes: a2 - Alternate breakpoint for unrolled loops
+ */
+
+ /*
+ * Solve for some register values now.
+ * Byte copy does not need t5 or t6.
+ */
+ mv t3, a0
+ add t4, a0, a2
+ add a4, a1, a2
+
+ /*
+ * Byte copy if copying less than (2 * SZREG) bytes. This can
+ * cause problems with the bulk copy implementation and is
+ * small enough not to bother.
+ */
+ andi t0, a2, -(2 * SZREG)
+ beqz t0, byte_copy
+
+ /*
+ * Now solve for t5 and t6.
+ */
+ andi t5, t3, -SZREG
+ andi t6, t4, -SZREG
+ /*
+ * If dest(Register t3) rounded down to the nearest naturally
+ * aligned SZREG address, does not equal dest, then add SZREG
+ * to find the low-bound of SZREG alignment in the dest memory
+ * region. Note that this could overshoot the dest memory
+ * region if n is less than SZREG. This is one reason why
+ * we always byte copy if n is less than SZREG.
+ * Otherwise, dest is already naturally aligned to SZREG.
+ */
+ beq t5, t3, 1f
+ addi t5, t5, SZREG
+ 1:
+
+ /*
+ * If the dest and src are co-aligned to SZREG, then there is
+ * no need for the full rigmarole of a full misaligned fixup copy.
+ * Instead, do a simpler co-aligned copy.
+ */
+ xor t0, a0, a1
+ andi t1, t0, (SZREG - 1)
+ beqz t1, coaligned_copy
+ /* Fall through to misaligned fixup copy */
+
+misaligned_fixup_copy:
+ bltu a1, a0, misaligned_fixup_copy_reverse
+
+misaligned_fixup_copy_forward:
+ jal t0, byte_copy_until_aligned_forward
+
+ andi a5, a1, (SZREG - 1) /* Find the alignment offset of src (a1) */
+ slli a6, a5, 3 /* Multiply by 8 to convert that to bits to shift */
+ sub a5, a1, t3 /* Find the difference between src and dest */
+ andi a1, a1, -SZREG /* Align the src pointer */
+ addi a2, t6, SZREG /* The other breakpoint for the unrolled loop*/
+
+ /*
+ * Compute The Inverse Shift
+ * a7 = XLEN - a6 = XLEN + -a6
+ * 2s complement negation to find the negative: -a6 = ~a6 + 1
+ * Add that to XLEN. XLEN = SZREG * 8.
+ */
+ not a7, a6
+ addi a7, a7, (SZREG * 8 + 1)
+
+ /*
+ * Fix Misalignment Copy Loop - Forward
+ * load_val0 = load_ptr[0];
+ * do {
+ * load_val1 = load_ptr[1];
+ * store_ptr += 2;
+ * store_ptr[0 - 2] = (load_val0 >> {a6}) | (load_val1 << {a7});
+ *
+ * if (store_ptr == {a2})
+ * break;
+ *
+ * load_val0 = load_ptr[2];
+ * load_ptr += 2;
+ * store_ptr[1 - 2] = (load_val1 >> {a6}) | (load_val0 << {a7});
+ *
+ * } while (store_ptr != store_ptr_end);
+ * store_ptr = store_ptr_end;
+ */
+
+ REG_L t0, (0 * SZREG)(a1)
+ 1:
+ REG_L t1, (1 * SZREG)(a1)
+ addi t3, t3, (2 * SZREG)
+ srl t0, t0, a6
+ sll t2, t1, a7
+ or t2, t0, t2
+ REG_S t2, ((0 * SZREG) - (2 * SZREG))(t3)
+
+ beq t3, a2, 2f
+
+ REG_L t0, (2 * SZREG)(a1)
+ addi a1, a1, (2 * SZREG)
+ srl t1, t1, a6
+ sll t2, t0, a7
+ or t2, t1, t2
+ REG_S t2, ((1 * SZREG) - (2 * SZREG))(t3)
+
+ bne t3, t6, 1b
+ 2:
+ mv t3, t6 /* Fix the dest pointer in case the loop was broken */
+
+ add a1, t3, a5 /* Restore the src pointer */
+ j byte_copy_forward /* Copy any remaining bytes */
+
+misaligned_fixup_copy_reverse:
+ jal t0, byte_copy_until_aligned_reverse
+
+ andi a5, a4, (SZREG - 1) /* Find the alignment offset of src (a4) */
+ slli a6, a5, 3 /* Multiply by 8 to convert that to bits to shift */
+ sub a5, a4, t4 /* Find the difference between src and dest */
+ andi a4, a4, -SZREG /* Align the src pointer */
+ addi a2, t5, -SZREG /* The other breakpoint for the unrolled loop*/
+
+ /*
+ * Compute The Inverse Shift
+ * a7 = XLEN - a6 = XLEN + -a6
+ * 2s complement negation to find the negative: -a6 = ~a6 + 1
+ * Add that to XLEN. XLEN = SZREG * 8.
+ */
+ not a7, a6
+ addi a7, a7, (SZREG * 8 + 1)
+
+ /*
+ * Fix Misalignment Copy Loop - Reverse
+ * load_val1 = load_ptr[0];
+ * do {
+ * load_val0 = load_ptr[-1];
+ * store_ptr -= 2;
+ * store_ptr[1] = (load_val0 >> {a6}) | (load_val1 << {a7});
+ *
+ * if (store_ptr == {a2})
+ * break;
+ *
+ * load_val1 = load_ptr[-2];
+ * load_ptr -= 2;
+ * store_ptr[0] = (load_val1 >> {a6}) | (load_val0 << {a7});
+ *
+ * } while (store_ptr != store_ptr_end);
+ * store_ptr = store_ptr_end;
+ */
+
+ REG_L t1, ( 0 * SZREG)(a4)
+ 1:
+ REG_L t0, (-1 * SZREG)(a4)
+ addi t4, t4, (-2 * SZREG)
+ sll t1, t1, a7
+ srl t2, t0, a6
+ or t2, t1, t2
+ REG_S t2, ( 1 * SZREG)(t4)
+
+ beq t4, a2, 2f
+
+ REG_L t1, (-2 * SZREG)(a4)
+ addi a4, a4, (-2 * SZREG)
+ sll t0, t0, a7
+ srl t2, t1, a6
+ or t2, t0, t2
+ REG_S t2, ( 0 * SZREG)(t4)
+
+ bne t4, t5, 1b
+ 2:
+ mv t4, t5 /* Fix the dest pointer in case the loop was broken */
+
+ add a4, t4, a5 /* Restore the src pointer */
+ j byte_copy_reverse /* Copy any remaining bytes */
+
+/*
+ * Simple copy loops for SZREG co-aligned memory locations.
+ * These also make calls to do byte copies for any unaligned
+ * data at their terminations.
+ */
+coaligned_copy:
+ bltu a1, a0, coaligned_copy_reverse
+
+coaligned_copy_forward:
+ jal t0, byte_copy_until_aligned_forward
+
+ 1:
+ REG_L t1, ( 0 * SZREG)(a1)
+ addi a1, a1, SZREG
+ addi t3, t3, SZREG
+ REG_S t1, (-1 * SZREG)(t3)
+ bne t3, t6, 1b
+
+ j byte_copy_forward /* Copy any remaining bytes */
+
+coaligned_copy_reverse:
+ jal t0, byte_copy_until_aligned_reverse
+
+ 1:
+ REG_L t1, (-1 * SZREG)(a4)
+ addi a4, a4, -SZREG
+ addi t4, t4, -SZREG
+ REG_S t1, ( 0 * SZREG)(t4)
+ bne t4, t5, 1b
+
+ j byte_copy_reverse /* Copy any remaining bytes */
+
+/*
+ * These are basically sub-functions within the function. They
+ * are used to byte copy until the dest pointer is in alignment.
+ * At which point, a bulk copy method can be used by the
+ * calling code. These work on the same registers as the bulk
+ * copy loops. Therefore, the register values can be picked
+ * up from where they were left and we avoid code duplication
+ * without any overhead except the call in and return jumps.
+ */
+byte_copy_until_aligned_forward:
+ beq t3, t5, 2f
+ 1:
+ lb t1, 0(a1)
+ addi a1, a1, 1
+ addi t3, t3, 1
+ sb t1, -1(t3)
+ bne t3, t5, 1b
+ 2:
+ jalr zero, 0x0(t0) /* Return to multibyte copy loop */
+
+byte_copy_until_aligned_reverse:
+ beq t4, t6, 2f
+ 1:
+ lb t1, -1(a4)
+ addi a4, a4, -1
+ addi t4, t4, -1
+ sb t1, 0(t4)
+ bne t4, t6, 1b
+ 2:
+ jalr zero, 0x0(t0) /* Return to multibyte copy loop */
+
+/*
+ * Simple byte copy loops.
+ * These will byte copy until they reach the end of data to copy.
+ * At that point, they will call to return from memmove.
+ */
+byte_copy:
+ bltu a1, a0, byte_copy_reverse
+
+byte_copy_forward:
+ beq t3, t4, 2f
+ 1:
+ lb t1, 0(a1)
+ addi a1, a1, 1
+ addi t3, t3, 1
+ sb t1, -1(t3)
+ bne t3, t4, 1b
+ 2:
+ ret
+
+byte_copy_reverse:
+ beq t4, t3, 2f
+ 1:
+ lb t1, -1(a4)
+ addi a4, a4, -1
+ addi t4, t4, -1
+ sb t1, 0(t4)
+ bne t4, t3, 1b
+ 2:
+
+return_from_memmove:
+ ret
+
+SYM_FUNC_END(memmove)
+SYM_FUNC_END(__memmove)
+SYM_FUNC_ALIAS(__pi_memmove, __memmove)
+SYM_FUNC_ALIAS(__pi___memmove, __memmove)
diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S
new file mode 100644
index 0000000000..34c5360c67
--- /dev/null
+++ b/arch/riscv/lib/memset.S
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2013 Regents of the University of California
+ */
+
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+/* void *memset(void *, int, size_t) */
+ENTRY(__memset)
+WEAK(memset)
+ move t0, a0 /* Preserve return value */
+
+ /* Defer to byte-oriented fill for small sizes */
+ sltiu a3, a2, 16
+ bnez a3, 4f
+
+ /*
+ * Round to nearest XLEN-aligned address
+ * greater than or equal to start address
+ */
+ addi a3, t0, SZREG-1
+ andi a3, a3, ~(SZREG-1)
+ beq a3, t0, 2f /* Skip if already aligned */
+ /* Handle initial misalignment */
+ sub a4, a3, t0
+1:
+ sb a1, 0(t0)
+ addi t0, t0, 1
+ bltu t0, a3, 1b
+ sub a2, a2, a4 /* Update count */
+
+2: /* Duff's device with 32 XLEN stores per iteration */
+ /* Broadcast value into all bytes */
+ andi a1, a1, 0xff
+ slli a3, a1, 8
+ or a1, a3, a1
+ slli a3, a1, 16
+ or a1, a3, a1
+#ifdef CONFIG_64BIT
+ slli a3, a1, 32
+ or a1, a3, a1
+#endif
+
+ /* Calculate end address */
+ andi a4, a2, ~(SZREG-1)
+ add a3, t0, a4
+
+ andi a4, a4, 31*SZREG /* Calculate remainder */
+ beqz a4, 3f /* Shortcut if no remainder */
+ neg a4, a4
+ addi a4, a4, 32*SZREG /* Calculate initial offset */
+
+ /* Adjust start address with offset */
+ sub t0, t0, a4
+
+ /* Jump into loop body */
+ /* Assumes 32-bit instruction lengths */
+ la a5, 3f
+#ifdef CONFIG_64BIT
+ srli a4, a4, 1
+#endif
+ add a5, a5, a4
+ jr a5
+3:
+ REG_S a1, 0(t0)
+ REG_S a1, SZREG(t0)
+ REG_S a1, 2*SZREG(t0)
+ REG_S a1, 3*SZREG(t0)
+ REG_S a1, 4*SZREG(t0)
+ REG_S a1, 5*SZREG(t0)
+ REG_S a1, 6*SZREG(t0)
+ REG_S a1, 7*SZREG(t0)
+ REG_S a1, 8*SZREG(t0)
+ REG_S a1, 9*SZREG(t0)
+ REG_S a1, 10*SZREG(t0)
+ REG_S a1, 11*SZREG(t0)
+ REG_S a1, 12*SZREG(t0)
+ REG_S a1, 13*SZREG(t0)
+ REG_S a1, 14*SZREG(t0)
+ REG_S a1, 15*SZREG(t0)
+ REG_S a1, 16*SZREG(t0)
+ REG_S a1, 17*SZREG(t0)
+ REG_S a1, 18*SZREG(t0)
+ REG_S a1, 19*SZREG(t0)
+ REG_S a1, 20*SZREG(t0)
+ REG_S a1, 21*SZREG(t0)
+ REG_S a1, 22*SZREG(t0)
+ REG_S a1, 23*SZREG(t0)
+ REG_S a1, 24*SZREG(t0)
+ REG_S a1, 25*SZREG(t0)
+ REG_S a1, 26*SZREG(t0)
+ REG_S a1, 27*SZREG(t0)
+ REG_S a1, 28*SZREG(t0)
+ REG_S a1, 29*SZREG(t0)
+ REG_S a1, 30*SZREG(t0)
+ REG_S a1, 31*SZREG(t0)
+ addi t0, t0, 32*SZREG
+ bltu t0, a3, 3b
+ andi a2, a2, SZREG-1 /* Update count */
+
+4:
+ /* Handle trailing misalignment */
+ beqz a2, 6f
+ add a3, t0, a2
+5:
+ sb a1, 0(t0)
+ addi t0, t0, 1
+ bltu t0, a3, 5b
+6:
+ ret
+END(__memset)
diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
new file mode 100644
index 0000000000..687b2bea5c
--- /dev/null
+++ b/arch/riscv/lib/strcmp.S
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/alternative-macros.h>
+#include <asm/hwcap.h>
+
+/* int strcmp(const char *cs, const char *ct) */
+SYM_FUNC_START(strcmp)
+
+ ALTERNATIVE("nop", "j strcmp_zbb", 0, RISCV_ISA_EXT_ZBB, CONFIG_RISCV_ISA_ZBB)
+
+ /*
+ * Returns
+ * a0 - comparison result, value like strcmp
+ *
+ * Parameters
+ * a0 - string1
+ * a1 - string2
+ *
+ * Clobbers
+ * t0, t1
+ */
+1:
+ lbu t0, 0(a0)
+ lbu t1, 0(a1)
+ addi a0, a0, 1
+ addi a1, a1, 1
+ bne t0, t1, 2f
+ bnez t0, 1b
+ li a0, 0
+ ret
+2:
+ /*
+ * strcmp only needs to return (< 0, 0, > 0) values
+ * not necessarily -1, 0, +1
+ */
+ sub a0, t0, t1
+ ret
+
+/*
+ * Variant of strcmp using the ZBB extension if available.
+ * The code was published as part of the bitmanip manual
+ * in Appendix A.
+ */
+#ifdef CONFIG_RISCV_ISA_ZBB
+strcmp_zbb:
+
+.option push
+.option arch,+zbb
+
+ /*
+ * Returns
+ * a0 - comparison result, value like strcmp
+ *
+ * Parameters
+ * a0 - string1
+ * a1 - string2
+ *
+ * Clobbers
+ * t0, t1, t2, t3, t4
+ */
+
+ or t2, a0, a1
+ li t4, -1
+ and t2, t2, SZREG-1
+ bnez t2, 3f
+
+ /* Main loop for aligned string. */
+ .p2align 3
+1:
+ REG_L t0, 0(a0)
+ REG_L t1, 0(a1)
+ orc.b t3, t0
+ bne t3, t4, 2f
+ addi a0, a0, SZREG
+ addi a1, a1, SZREG
+ beq t0, t1, 1b
+
+ /*
+ * Words don't match, and no null byte in the first
+ * word. Get bytes in big-endian order and compare.
+ */
+#ifndef CONFIG_CPU_BIG_ENDIAN
+ rev8 t0, t0
+ rev8 t1, t1
+#endif
+
+ /* Synthesize (t0 >= t1) ? 1 : -1 in a branchless sequence. */
+ sltu a0, t0, t1
+ neg a0, a0
+ ori a0, a0, 1
+ ret
+
+2:
+ /*
+ * Found a null byte.
+ * If words don't match, fall back to simple loop.
+ */
+ bne t0, t1, 3f
+
+ /* Otherwise, strings are equal. */
+ li a0, 0
+ ret
+
+ /* Simple loop for misaligned strings. */
+ .p2align 3
+3:
+ lbu t0, 0(a0)
+ lbu t1, 0(a1)
+ addi a0, a0, 1
+ addi a1, a1, 1
+ bne t0, t1, 4f
+ bnez t0, 3b
+
+4:
+ sub a0, t0, t1
+ ret
+
+.option pop
+#endif
+SYM_FUNC_END(strcmp)
diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
new file mode 100644
index 0000000000..8ae3064e45
--- /dev/null
+++ b/arch/riscv/lib/strlen.S
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/alternative-macros.h>
+#include <asm/hwcap.h>
+
+/* int strlen(const char *s) */
+SYM_FUNC_START(strlen)
+
+ ALTERNATIVE("nop", "j strlen_zbb", 0, RISCV_ISA_EXT_ZBB, CONFIG_RISCV_ISA_ZBB)
+
+ /*
+ * Returns
+ * a0 - string length
+ *
+ * Parameters
+ * a0 - String to measure
+ *
+ * Clobbers:
+ * t0, t1
+ */
+ mv t1, a0
+1:
+ lbu t0, 0(t1)
+ beqz t0, 2f
+ addi t1, t1, 1
+ j 1b
+2:
+ sub a0, t1, a0
+ ret
+
+/*
+ * Variant of strlen using the ZBB extension if available
+ */
+#ifdef CONFIG_RISCV_ISA_ZBB
+strlen_zbb:
+
+#ifdef CONFIG_CPU_BIG_ENDIAN
+# define CZ clz
+# define SHIFT sll
+#else
+# define CZ ctz
+# define SHIFT srl
+#endif
+
+.option push
+.option arch,+zbb
+
+ /*
+ * Returns
+ * a0 - string length
+ *
+ * Parameters
+ * a0 - String to measure
+ *
+ * Clobbers
+ * t0, t1, t2, t3
+ */
+
+ /* Number of irrelevant bytes in the first word. */
+ andi t2, a0, SZREG-1
+
+ /* Align pointer. */
+ andi t0, a0, -SZREG
+
+ li t3, SZREG
+ sub t3, t3, t2
+ slli t2, t2, 3
+
+ /* Get the first word. */
+ REG_L t1, 0(t0)
+
+ /*
+ * Shift away the partial data we loaded to remove the irrelevant bytes
+ * preceding the string with the effect of adding NUL bytes at the
+ * end of the string's first word.
+ */
+ SHIFT t1, t1, t2
+
+ /* Convert non-NUL into 0xff and NUL into 0x00. */
+ orc.b t1, t1
+
+ /* Convert non-NUL into 0x00 and NUL into 0xff. */
+ not t1, t1
+
+ /*
+ * Search for the first set bit (corresponding to a NUL byte in the
+ * original chunk).
+ */
+ CZ t1, t1
+
+ /*
+ * The first chunk is special: compare against the number
+ * of valid bytes in this chunk.
+ */
+ srli a0, t1, 3
+ bgtu t3, a0, 2f
+
+ /* Prepare for the word comparison loop. */
+ addi t2, t0, SZREG
+ li t3, -1
+
+ /*
+ * Our critical loop is 4 instructions and processes data in
+ * 4 byte or 8 byte chunks.
+ */
+ .p2align 3
+1:
+ REG_L t1, SZREG(t0)
+ addi t0, t0, SZREG
+ orc.b t1, t1
+ beq t1, t3, 1b
+
+ not t1, t1
+ CZ t1, t1
+ srli t1, t1, 3
+
+ /* Get number of processed bytes. */
+ sub t2, t0, t2
+
+ /* Add number of characters in the first word. */
+ add a0, a0, t2
+
+ /* Add number of characters in the last word. */
+ add a0, a0, t1
+2:
+ ret
+
+.option pop
+#endif
+SYM_FUNC_END(strlen)
+SYM_FUNC_ALIAS(__pi_strlen, strlen)
diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
new file mode 100644
index 0000000000..aba5b31486
--- /dev/null
+++ b/arch/riscv/lib/strncmp.S
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/alternative-macros.h>
+#include <asm/hwcap.h>
+
+/* int strncmp(const char *cs, const char *ct, size_t count) */
+SYM_FUNC_START(strncmp)
+
+ ALTERNATIVE("nop", "j strncmp_zbb", 0, RISCV_ISA_EXT_ZBB, CONFIG_RISCV_ISA_ZBB)
+
+ /*
+ * Returns
+ * a0 - comparison result, value like strncmp
+ *
+ * Parameters
+ * a0 - string1
+ * a1 - string2
+ * a2 - number of characters to compare
+ *
+ * Clobbers
+ * t0, t1, t2
+ */
+ li t2, 0
+1:
+ beq a2, t2, 2f
+ lbu t0, 0(a0)
+ lbu t1, 0(a1)
+ addi a0, a0, 1
+ addi a1, a1, 1
+ bne t0, t1, 3f
+ addi t2, t2, 1
+ bnez t0, 1b
+2:
+ li a0, 0
+ ret
+3:
+ /*
+ * strncmp only needs to return (< 0, 0, > 0) values
+ * not necessarily -1, 0, +1
+ */
+ sub a0, t0, t1
+ ret
+
+/*
+ * Variant of strncmp using the ZBB extension if available
+ */
+#ifdef CONFIG_RISCV_ISA_ZBB
+strncmp_zbb:
+
+.option push
+.option arch,+zbb
+
+ /*
+ * Returns
+ * a0 - comparison result, like strncmp
+ *
+ * Parameters
+ * a0 - string1
+ * a1 - string2
+ * a2 - number of characters to compare
+ *
+ * Clobbers
+ * t0, t1, t2, t3, t4, t5, t6
+ */
+
+ or t2, a0, a1
+ li t5, -1
+ and t2, t2, SZREG-1
+ add t4, a0, a2
+ bnez t2, 3f
+
+ /* Adjust limit for fast-path. */
+ andi t6, t4, -SZREG
+
+ /* Main loop for aligned string. */
+ .p2align 3
+1:
+ bge a0, t6, 3f
+ REG_L t0, 0(a0)
+ REG_L t1, 0(a1)
+ orc.b t3, t0
+ bne t3, t5, 2f
+ orc.b t3, t1
+ bne t3, t5, 2f
+ addi a0, a0, SZREG
+ addi a1, a1, SZREG
+ beq t0, t1, 1b
+
+ /*
+ * Words don't match, and no null byte in the first
+ * word. Get bytes in big-endian order and compare.
+ */
+#ifndef CONFIG_CPU_BIG_ENDIAN
+ rev8 t0, t0
+ rev8 t1, t1
+#endif
+
+ /* Synthesize (t0 >= t1) ? 1 : -1 in a branchless sequence. */
+ sltu a0, t0, t1
+ neg a0, a0
+ ori a0, a0, 1
+ ret
+
+2:
+ /*
+ * Found a null byte.
+ * If words don't match, fall back to simple loop.
+ */
+ bne t0, t1, 3f
+
+ /* Otherwise, strings are equal. */
+ li a0, 0
+ ret
+
+ /* Simple loop for misaligned strings. */
+ .p2align 3
+3:
+ bge a0, t4, 5f
+ lbu t0, 0(a0)
+ lbu t1, 0(a1)
+ addi a0, a0, 1
+ addi a1, a1, 1
+ bne t0, t1, 4f
+ bnez t0, 3b
+
+4:
+ sub a0, t0, t1
+ ret
+
+5:
+ li a0, 0
+ ret
+
+.option pop
+#endif
+SYM_FUNC_END(strncmp)
diff --git a/arch/riscv/lib/tishift.S b/arch/riscv/lib/tishift.S
new file mode 100644
index 0000000000..ef90075c4b
--- /dev/null
+++ b/arch/riscv/lib/tishift.S
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2018 Free Software Foundation, Inc.
+ */
+
+#include <linux/linkage.h>
+#include <asm-generic/export.h>
+
+SYM_FUNC_START(__lshrti3)
+ beqz a2, .L1
+ li a5,64
+ sub a5,a5,a2
+ sext.w a4,a5
+ blez a5, .L2
+ sext.w a2,a2
+ srl a0,a0,a2
+ sll a4,a1,a4
+ srl a2,a1,a2
+ or a0,a0,a4
+ mv a1,a2
+.L1:
+ ret
+.L2:
+ negw a0,a4
+ li a2,0
+ srl a0,a1,a0
+ mv a1,a2
+ ret
+SYM_FUNC_END(__lshrti3)
+EXPORT_SYMBOL(__lshrti3)
+
+SYM_FUNC_START(__ashrti3)
+ beqz a2, .L3
+ li a5,64
+ sub a5,a5,a2
+ sext.w a4,a5
+ blez a5, .L4
+ sext.w a2,a2
+ srl a0,a0,a2
+ sll a4,a1,a4
+ sra a2,a1,a2
+ or a0,a0,a4
+ mv a1,a2
+.L3:
+ ret
+.L4:
+ negw a0,a4
+ srai a2,a1,0x3f
+ sra a0,a1,a0
+ mv a1,a2
+ ret
+SYM_FUNC_END(__ashrti3)
+EXPORT_SYMBOL(__ashrti3)
+
+SYM_FUNC_START(__ashlti3)
+ beqz a2, .L5
+ li a5,64
+ sub a5,a5,a2
+ sext.w a4,a5
+ blez a5, .L6
+ sext.w a2,a2
+ sll a1,a1,a2
+ srl a4,a0,a4
+ sll a2,a0,a2
+ or a1,a1,a4
+ mv a0,a2
+.L5:
+ ret
+.L6:
+ negw a1,a4
+ li a2,0
+ sll a1,a0,a1
+ mv a0,a2
+ ret
+SYM_FUNC_END(__ashlti3)
+EXPORT_SYMBOL(__ashlti3)
diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
new file mode 100644
index 0000000000..09b47ebacf
--- /dev/null
+++ b/arch/riscv/lib/uaccess.S
@@ -0,0 +1,237 @@
+#include <linux/linkage.h>
+#include <asm-generic/export.h>
+#include <asm/asm.h>
+#include <asm/asm-extable.h>
+#include <asm/csr.h>
+
+ .macro fixup op reg addr lbl
+100:
+ \op \reg, \addr
+ _asm_extable 100b, \lbl
+ .endm
+
+ENTRY(__asm_copy_to_user)
+ENTRY(__asm_copy_from_user)
+
+ /* Enable access to user memory */
+ li t6, SR_SUM
+ csrs CSR_STATUS, t6
+
+ /*
+ * Save the terminal address which will be used to compute the number
+ * of bytes copied in case of a fixup exception.
+ */
+ add t5, a0, a2
+
+ /*
+ * Register allocation for code below:
+ * a0 - start of uncopied dst
+ * a1 - start of uncopied src
+ * a2 - size
+ * t0 - end of uncopied dst
+ */
+ add t0, a0, a2
+
+ /*
+ * Use byte copy only if too small.
+ * SZREG holds 4 for RV32 and 8 for RV64
+ */
+ li a3, 9*SZREG /* size must be larger than size in word_copy */
+ bltu a2, a3, .Lbyte_copy_tail
+
+ /*
+ * Copy first bytes until dst is aligned to word boundary.
+ * a0 - start of dst
+ * t1 - start of aligned dst
+ */
+ addi t1, a0, SZREG-1
+ andi t1, t1, ~(SZREG-1)
+ /* dst is already aligned, skip */
+ beq a0, t1, .Lskip_align_dst
+1:
+ /* a5 - one byte for copying data */
+ fixup lb a5, 0(a1), 10f
+ addi a1, a1, 1 /* src */
+ fixup sb a5, 0(a0), 10f
+ addi a0, a0, 1 /* dst */
+ bltu a0, t1, 1b /* t1 - start of aligned dst */
+
+.Lskip_align_dst:
+ /*
+ * Now dst is aligned.
+ * Use shift-copy if src is misaligned.
+ * Use word-copy if both src and dst are aligned because
+ * can not use shift-copy which do not require shifting
+ */
+ /* a1 - start of src */
+ andi a3, a1, SZREG-1
+ bnez a3, .Lshift_copy
+
+.Lword_copy:
+ /*
+ * Both src and dst are aligned, unrolled word copy
+ *
+ * a0 - start of aligned dst
+ * a1 - start of aligned src
+ * t0 - end of aligned dst
+ */
+ addi t0, t0, -(8*SZREG) /* not to over run */
+2:
+ fixup REG_L a4, 0(a1), 10f
+ fixup REG_L a5, SZREG(a1), 10f
+ fixup REG_L a6, 2*SZREG(a1), 10f
+ fixup REG_L a7, 3*SZREG(a1), 10f
+ fixup REG_L t1, 4*SZREG(a1), 10f
+ fixup REG_L t2, 5*SZREG(a1), 10f
+ fixup REG_L t3, 6*SZREG(a1), 10f
+ fixup REG_L t4, 7*SZREG(a1), 10f
+ fixup REG_S a4, 0(a0), 10f
+ fixup REG_S a5, SZREG(a0), 10f
+ fixup REG_S a6, 2*SZREG(a0), 10f
+ fixup REG_S a7, 3*SZREG(a0), 10f
+ fixup REG_S t1, 4*SZREG(a0), 10f
+ fixup REG_S t2, 5*SZREG(a0), 10f
+ fixup REG_S t3, 6*SZREG(a0), 10f
+ fixup REG_S t4, 7*SZREG(a0), 10f
+ addi a0, a0, 8*SZREG
+ addi a1, a1, 8*SZREG
+ bltu a0, t0, 2b
+
+ addi t0, t0, 8*SZREG /* revert to original value */
+ j .Lbyte_copy_tail
+
+.Lshift_copy:
+
+ /*
+ * Word copy with shifting.
+ * For misaligned copy we still perform aligned word copy, but
+ * we need to use the value fetched from the previous iteration and
+ * do some shifts.
+ * This is safe because reading is less than a word size.
+ *
+ * a0 - start of aligned dst
+ * a1 - start of src
+ * a3 - a1 & mask:(SZREG-1)
+ * t0 - end of uncopied dst
+ * t1 - end of aligned dst
+ */
+ /* calculating aligned word boundary for dst */
+ andi t1, t0, ~(SZREG-1)
+ /* Converting unaligned src to aligned src */
+ andi a1, a1, ~(SZREG-1)
+
+ /*
+ * Calculate shifts
+ * t3 - prev shift
+ * t4 - current shift
+ */
+ slli t3, a3, 3 /* converting bytes in a3 to bits */
+ li a5, SZREG*8
+ sub t4, a5, t3
+
+ /* Load the first word to combine with second word */
+ fixup REG_L a5, 0(a1), 10f
+
+3:
+ /* Main shifting copy
+ *
+ * a0 - start of aligned dst
+ * a1 - start of aligned src
+ * t1 - end of aligned dst
+ */
+
+ /* At least one iteration will be executed */
+ srl a4, a5, t3
+ fixup REG_L a5, SZREG(a1), 10f
+ addi a1, a1, SZREG
+ sll a2, a5, t4
+ or a2, a2, a4
+ fixup REG_S a2, 0(a0), 10f
+ addi a0, a0, SZREG
+ bltu a0, t1, 3b
+
+ /* Revert src to original unaligned value */
+ add a1, a1, a3
+
+.Lbyte_copy_tail:
+ /*
+ * Byte copy anything left.
+ *
+ * a0 - start of remaining dst
+ * a1 - start of remaining src
+ * t0 - end of remaining dst
+ */
+ bgeu a0, t0, .Lout_copy_user /* check if end of copy */
+4:
+ fixup lb a5, 0(a1), 10f
+ addi a1, a1, 1 /* src */
+ fixup sb a5, 0(a0), 10f
+ addi a0, a0, 1 /* dst */
+ bltu a0, t0, 4b /* t0 - end of dst */
+
+.Lout_copy_user:
+ /* Disable access to user memory */
+ csrc CSR_STATUS, t6
+ li a0, 0
+ ret
+
+ /* Exception fixup code */
+10:
+ /* Disable access to user memory */
+ csrc CSR_STATUS, t6
+ sub a0, t5, a0
+ ret
+ENDPROC(__asm_copy_to_user)
+ENDPROC(__asm_copy_from_user)
+EXPORT_SYMBOL(__asm_copy_to_user)
+EXPORT_SYMBOL(__asm_copy_from_user)
+
+
+ENTRY(__clear_user)
+
+ /* Enable access to user memory */
+ li t6, SR_SUM
+ csrs CSR_STATUS, t6
+
+ add a3, a0, a1
+ addi t0, a0, SZREG-1
+ andi t1, a3, ~(SZREG-1)
+ andi t0, t0, ~(SZREG-1)
+ /*
+ * a3: terminal address of target region
+ * t0: lowest doubleword-aligned address in target region
+ * t1: highest doubleword-aligned address in target region
+ */
+ bgeu t0, t1, 2f
+ bltu a0, t0, 4f
+1:
+ fixup REG_S, zero, (a0), 11f
+ addi a0, a0, SZREG
+ bltu a0, t1, 1b
+2:
+ bltu a0, a3, 5f
+
+3:
+ /* Disable access to user memory */
+ csrc CSR_STATUS, t6
+ li a0, 0
+ ret
+4: /* Edge case: unalignment */
+ fixup sb, zero, (a0), 11f
+ addi a0, a0, 1
+ bltu a0, t0, 4b
+ j 1b
+5: /* Edge case: remainder */
+ fixup sb, zero, (a0), 11f
+ addi a0, a0, 1
+ bltu a0, a3, 5b
+ j 3b
+
+ /* Exception fixup code */
+11:
+ /* Disable access to user memory */
+ csrc CSR_STATUS, t6
+ sub a0, a3, a0
+ ret
+ENDPROC(__clear_user)
+EXPORT_SYMBOL(__clear_user)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-09 19:53:07 +0000