summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/align.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/align.c')
-rw-r--r--arch/powerpc/kernel/align.c364
1 files changed, 364 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
new file mode 100644
index 000000000..3e37ece06
--- /dev/null
+++ b/arch/powerpc/kernel/align.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* align.c - handle alignment exceptions for the Power PC.
+ *
+ * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
+ * Copyright (c) 1998-1999 TiVo, Inc.
+ * PowerPC 403GCX modifications.
+ * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
+ * PowerPC 403GCX/405GP modifications.
+ * Copyright (c) 2001-2002 PPC64 team, IBM Corp
+ * 64-bit and Power4 support
+ * Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
+ * <benh@kernel.crashing.org>
+ * Merge ppc32 and ppc64 implementations
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <asm/processor.h>
+#include <linux/uaccess.h>
+#include <asm/cache.h>
+#include <asm/cputable.h>
+#include <asm/emulated_ops.h>
+#include <asm/switch_to.h>
+#include <asm/disassemble.h>
+#include <asm/cpu_has_feature.h>
+#include <asm/sstep.h>
+#include <asm/inst.h>
+
+struct aligninfo {
+ unsigned char len;
+ unsigned char flags;
+};
+
+
+#define INVALID { 0, 0 }
+
+/* Bits in the flags field */
+#define LD 0 /* load */
+#define ST 1 /* store */
+#define SE 2 /* sign-extend value, or FP ld/st as word */
+#define SW 0x20 /* byte swap */
+#define E4 0x40 /* SPE endianness is word */
+#define E8 0x80 /* SPE endianness is double word */
+
+#ifdef CONFIG_SPE
+
+static struct aligninfo spe_aligninfo[32] = {
+ { 8, LD+E8 }, /* 0 00 00: evldd[x] */
+ { 8, LD+E4 }, /* 0 00 01: evldw[x] */
+ { 8, LD }, /* 0 00 10: evldh[x] */
+ INVALID, /* 0 00 11 */
+ { 2, LD }, /* 0 01 00: evlhhesplat[x] */
+ INVALID, /* 0 01 01 */
+ { 2, LD }, /* 0 01 10: evlhhousplat[x] */
+ { 2, LD+SE }, /* 0 01 11: evlhhossplat[x] */
+ { 4, LD }, /* 0 10 00: evlwhe[x] */
+ INVALID, /* 0 10 01 */
+ { 4, LD }, /* 0 10 10: evlwhou[x] */
+ { 4, LD+SE }, /* 0 10 11: evlwhos[x] */
+ { 4, LD+E4 }, /* 0 11 00: evlwwsplat[x] */
+ INVALID, /* 0 11 01 */
+ { 4, LD }, /* 0 11 10: evlwhsplat[x] */
+ INVALID, /* 0 11 11 */
+
+ { 8, ST+E8 }, /* 1 00 00: evstdd[x] */
+ { 8, ST+E4 }, /* 1 00 01: evstdw[x] */
+ { 8, ST }, /* 1 00 10: evstdh[x] */
+ INVALID, /* 1 00 11 */
+ INVALID, /* 1 01 00 */
+ INVALID, /* 1 01 01 */
+ INVALID, /* 1 01 10 */
+ INVALID, /* 1 01 11 */
+ { 4, ST }, /* 1 10 00: evstwhe[x] */
+ INVALID, /* 1 10 01 */
+ { 4, ST }, /* 1 10 10: evstwho[x] */
+ INVALID, /* 1 10 11 */
+ { 4, ST+E4 }, /* 1 11 00: evstwwe[x] */
+ INVALID, /* 1 11 01 */
+ { 4, ST+E4 }, /* 1 11 10: evstwwo[x] */
+ INVALID, /* 1 11 11 */
+};
+
+#define EVLDD 0x00
+#define EVLDW 0x01
+#define EVLDH 0x02
+#define EVLHHESPLAT 0x04
+#define EVLHHOUSPLAT 0x06
+#define EVLHHOSSPLAT 0x07
+#define EVLWHE 0x08
+#define EVLWHOU 0x0A
+#define EVLWHOS 0x0B
+#define EVLWWSPLAT 0x0C
+#define EVLWHSPLAT 0x0E
+#define EVSTDD 0x10
+#define EVSTDW 0x11
+#define EVSTDH 0x12
+#define EVSTWHE 0x18
+#define EVSTWHO 0x1A
+#define EVSTWWE 0x1C
+#define EVSTWWO 0x1E
+
+/*
+ * Emulate SPE loads and stores.
+ * Only Book-E has these instructions, and it does true little-endian,
+ * so we don't need the address swizzling.
+ */
+static int emulate_spe(struct pt_regs *regs, unsigned int reg,
+ ppc_inst_t ppc_instr)
+{
+ union {
+ u64 ll;
+ u32 w[2];
+ u16 h[4];
+ u8 v[8];
+ } data, temp;
+ unsigned char __user *p, *addr;
+ unsigned long *evr = &current->thread.evr[reg];
+ unsigned int nb, flags, instr;
+
+ instr = ppc_inst_val(ppc_instr);
+ instr = (instr >> 1) & 0x1f;
+
+ /* DAR has the operand effective address */
+ addr = (unsigned char __user *)regs->dar;
+
+ nb = spe_aligninfo[instr].len;
+ flags = spe_aligninfo[instr].flags;
+
+ /* userland only */
+ if (unlikely(!user_mode(regs)))
+ return 0;
+
+ flush_spe_to_thread(current);
+
+ /* If we are loading, get the data from user space, else
+ * get it from register values
+ */
+ if (flags & ST) {
+ data.ll = 0;
+ switch (instr) {
+ case EVSTDD:
+ case EVSTDW:
+ case EVSTDH:
+ data.w[0] = *evr;
+ data.w[1] = regs->gpr[reg];
+ break;
+ case EVSTWHE:
+ data.h[2] = *evr >> 16;
+ data.h[3] = regs->gpr[reg] >> 16;
+ break;
+ case EVSTWHO:
+ data.h[2] = *evr & 0xffff;
+ data.h[3] = regs->gpr[reg] & 0xffff;
+ break;
+ case EVSTWWE:
+ data.w[1] = *evr;
+ break;
+ case EVSTWWO:
+ data.w[1] = regs->gpr[reg];
+ break;
+ default:
+ return -EINVAL;
+ }
+ } else {
+ temp.ll = data.ll = 0;
+ p = addr;
+
+ if (!user_read_access_begin(addr, nb))
+ return -EFAULT;
+
+ switch (nb) {
+ case 8:
+ unsafe_get_user(temp.v[0], p++, Efault_read);
+ unsafe_get_user(temp.v[1], p++, Efault_read);
+ unsafe_get_user(temp.v[2], p++, Efault_read);
+ unsafe_get_user(temp.v[3], p++, Efault_read);
+ fallthrough;
+ case 4:
+ unsafe_get_user(temp.v[4], p++, Efault_read);
+ unsafe_get_user(temp.v[5], p++, Efault_read);
+ fallthrough;
+ case 2:
+ unsafe_get_user(temp.v[6], p++, Efault_read);
+ unsafe_get_user(temp.v[7], p++, Efault_read);
+ }
+ user_read_access_end();
+
+ switch (instr) {
+ case EVLDD:
+ case EVLDW:
+ case EVLDH:
+ data.ll = temp.ll;
+ break;
+ case EVLHHESPLAT:
+ data.h[0] = temp.h[3];
+ data.h[2] = temp.h[3];
+ break;
+ case EVLHHOUSPLAT:
+ case EVLHHOSSPLAT:
+ data.h[1] = temp.h[3];
+ data.h[3] = temp.h[3];
+ break;
+ case EVLWHE:
+ data.h[0] = temp.h[2];
+ data.h[2] = temp.h[3];
+ break;
+ case EVLWHOU:
+ case EVLWHOS:
+ data.h[1] = temp.h[2];
+ data.h[3] = temp.h[3];
+ break;
+ case EVLWWSPLAT:
+ data.w[0] = temp.w[1];
+ data.w[1] = temp.w[1];
+ break;
+ case EVLWHSPLAT:
+ data.h[0] = temp.h[2];
+ data.h[1] = temp.h[2];
+ data.h[2] = temp.h[3];
+ data.h[3] = temp.h[3];
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ if (flags & SW) {
+ switch (flags & 0xf0) {
+ case E8:
+ data.ll = swab64(data.ll);
+ break;
+ case E4:
+ data.w[0] = swab32(data.w[0]);
+ data.w[1] = swab32(data.w[1]);
+ break;
+ /* Its half word endian */
+ default:
+ data.h[0] = swab16(data.h[0]);
+ data.h[1] = swab16(data.h[1]);
+ data.h[2] = swab16(data.h[2]);
+ data.h[3] = swab16(data.h[3]);
+ break;
+ }
+ }
+
+ if (flags & SE) {
+ data.w[0] = (s16)data.h[1];
+ data.w[1] = (s16)data.h[3];
+ }
+
+ /* Store result to memory or update registers */
+ if (flags & ST) {
+ p = addr;
+
+ if (!user_write_access_begin(addr, nb))
+ return -EFAULT;
+
+ switch (nb) {
+ case 8:
+ unsafe_put_user(data.v[0], p++, Efault_write);
+ unsafe_put_user(data.v[1], p++, Efault_write);
+ unsafe_put_user(data.v[2], p++, Efault_write);
+ unsafe_put_user(data.v[3], p++, Efault_write);
+ fallthrough;
+ case 4:
+ unsafe_put_user(data.v[4], p++, Efault_write);
+ unsafe_put_user(data.v[5], p++, Efault_write);
+ fallthrough;
+ case 2:
+ unsafe_put_user(data.v[6], p++, Efault_write);
+ unsafe_put_user(data.v[7], p++, Efault_write);
+ }
+ user_write_access_end();
+ } else {
+ *evr = data.w[0];
+ regs->gpr[reg] = data.w[1];
+ }
+
+ return 1;
+
+Efault_read:
+ user_read_access_end();
+ return -EFAULT;
+
+Efault_write:
+ user_write_access_end();
+ return -EFAULT;
+}
+#endif /* CONFIG_SPE */
+
+/*
+ * Called on alignment exception. Attempts to fixup
+ *
+ * Return 1 on success
+ * Return 0 if unable to handle the interrupt
+ * Return -EFAULT if data address is bad
+ * Other negative return values indicate that the instruction can't
+ * be emulated, and the process should be given a SIGBUS.
+ */
+
+int fix_alignment(struct pt_regs *regs)
+{
+ ppc_inst_t instr;
+ struct instruction_op op;
+ int r, type;
+
+ if (is_kernel_addr(regs->nip))
+ r = copy_inst_from_kernel_nofault(&instr, (void *)regs->nip);
+ else
+ r = __get_user_instr(instr, (void __user *)regs->nip);
+
+ if (unlikely(r))
+ return -EFAULT;
+ if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
+ /* We don't handle PPC little-endian any more... */
+ if (cpu_has_feature(CPU_FTR_PPC_LE))
+ return -EIO;
+ instr = ppc_inst_swab(instr);
+ }
+
+#ifdef CONFIG_SPE
+ if (ppc_inst_primary_opcode(instr) == 0x4) {
+ int reg = (ppc_inst_val(instr) >> 21) & 0x1f;
+ PPC_WARN_ALIGNMENT(spe, regs);
+ return emulate_spe(regs, reg, instr);
+ }
+#endif
+
+
+ /*
+ * ISA 3.0 (such as P9) copy, copy_first, paste and paste_last alignment
+ * check.
+ *
+ * Send a SIGBUS to the process that caused the fault.
+ *
+ * We do not emulate these because paste may contain additional metadata
+ * when pasting to a co-processor. Furthermore, paste_last is the
+ * synchronisation point for preceding copy/paste sequences.
+ */
+ if ((ppc_inst_val(instr) & 0xfc0006fe) == (PPC_INST_COPY & 0xfc0006fe))
+ return -EIO;
+
+ r = analyse_instr(&op, regs, instr);
+ if (r < 0)
+ return -EINVAL;
+
+ type = GETTYPE(op.type);
+ if (!OP_IS_LOAD_STORE(type)) {
+ if (op.type != CACHEOP + DCBZ)
+ return -EINVAL;
+ PPC_WARN_ALIGNMENT(dcbz, regs);
+ WARN_ON_ONCE(!user_mode(regs));
+ r = emulate_dcbz(op.ea, regs);
+ } else {
+ if (type == LARX || type == STCX)
+ return -EIO;
+ PPC_WARN_ALIGNMENT(unaligned, regs);
+ r = emulate_loadstore(regs, &op);
+ }
+
+ if (!r)
+ return 1;
+ return r;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 18:22:12 +0000