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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/loongarch/kernel/alternative.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/loongarch/kernel/alternative.c')
-rw-r--r--arch/loongarch/kernel/alternative.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/alternative.c b/arch/loongarch/kernel/alternative.c
new file mode 100644
index 0000000000..4ad13847e9
--- /dev/null
+++ b/arch/loongarch/kernel/alternative.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <asm/alternative.h>
+#include <asm/cacheflush.h>
+#include <asm/inst.h>
+#include <asm/sections.h>
+
+int __read_mostly alternatives_patched;
+
+EXPORT_SYMBOL_GPL(alternatives_patched);
+
+#define MAX_PATCH_SIZE (((u8)(-1)) / LOONGARCH_INSN_SIZE)
+
+static int __initdata_or_module debug_alternative;
+
+static int __init debug_alt(char *str)
+{
+ debug_alternative = 1;
+ return 1;
+}
+__setup("debug-alternative", debug_alt);
+
+#define DPRINTK(fmt, args...) \
+do { \
+ if (debug_alternative) \
+ printk(KERN_DEBUG "%s: " fmt "\n", __func__, ##args); \
+} while (0)
+
+#define DUMP_WORDS(buf, count, fmt, args...) \
+do { \
+ if (unlikely(debug_alternative)) { \
+ int _j; \
+ union loongarch_instruction *_buf = buf; \
+ \
+ if (!(count)) \
+ break; \
+ \
+ printk(KERN_DEBUG fmt, ##args); \
+ for (_j = 0; _j < count - 1; _j++) \
+ printk(KERN_CONT "<%08x> ", _buf[_j].word); \
+ printk(KERN_CONT "<%08x>\n", _buf[_j].word); \
+ } \
+} while (0)
+
+/* Use this to add nops to a buffer, then text_poke the whole buffer. */
+static void __init_or_module add_nops(union loongarch_instruction *insn, int count)
+{
+ while (count--) {
+ insn->word = INSN_NOP;
+ insn++;
+ }
+}
+
+/* Is the jump addr in local .altinstructions */
+static inline bool in_alt_jump(unsigned long jump, void *start, void *end)
+{
+ return jump >= (unsigned long)start && jump < (unsigned long)end;
+}
+
+static void __init_or_module recompute_jump(union loongarch_instruction *buf,
+ union loongarch_instruction *dest, union loongarch_instruction *src,
+ void *start, void *end)
+{
+ unsigned int si, si_l, si_h;
+ unsigned long cur_pc, jump_addr, pc;
+ long offset;
+
+ cur_pc = (unsigned long)src;
+ pc = (unsigned long)dest;
+
+ si_l = src->reg0i26_format.immediate_l;
+ si_h = src->reg0i26_format.immediate_h;
+ switch (src->reg0i26_format.opcode) {
+ case b_op:
+ case bl_op:
+ jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
+ if (in_alt_jump(jump_addr, start, end))
+ return;
+ offset = jump_addr - pc;
+ BUG_ON(offset < -SZ_128M || offset >= SZ_128M);
+ offset >>= 2;
+ buf->reg0i26_format.immediate_h = offset >> 16;
+ buf->reg0i26_format.immediate_l = offset;
+ return;
+ }
+
+ si_l = src->reg1i21_format.immediate_l;
+ si_h = src->reg1i21_format.immediate_h;
+ switch (src->reg1i21_format.opcode) {
+ case bceqz_op: /* bceqz_op = bcnez_op */
+ BUG_ON(buf->reg1i21_format.rj & BIT(4));
+ fallthrough;
+ case beqz_op:
+ case bnez_op:
+ jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
+ if (in_alt_jump(jump_addr, start, end))
+ return;
+ offset = jump_addr - pc;
+ BUG_ON(offset < -SZ_4M || offset >= SZ_4M);
+ offset >>= 2;
+ buf->reg1i21_format.immediate_h = offset >> 16;
+ buf->reg1i21_format.immediate_l = offset;
+ return;
+ }
+
+ si = src->reg2i16_format.immediate;
+ switch (src->reg2i16_format.opcode) {
+ case beq_op:
+ case bne_op:
+ case blt_op:
+ case bge_op:
+ case bltu_op:
+ case bgeu_op:
+ jump_addr = cur_pc + sign_extend64(si << 2, 17);
+ if (in_alt_jump(jump_addr, start, end))
+ return;
+ offset = jump_addr - pc;
+ BUG_ON(offset < -SZ_128K || offset >= SZ_128K);
+ offset >>= 2;
+ buf->reg2i16_format.immediate = offset;
+ return;
+ }
+}
+
+static int __init_or_module copy_alt_insns(union loongarch_instruction *buf,
+ union loongarch_instruction *dest, union loongarch_instruction *src, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++) {
+ buf[i].word = src[i].word;
+
+ if (is_pc_ins(&src[i])) {
+ pr_err("Not support pcrel instruction at present!");
+ return -EINVAL;
+ }
+
+ if (is_branch_ins(&src[i]) &&
+ src[i].reg2i16_format.opcode != jirl_op) {
+ recompute_jump(&buf[i], &dest[i], &src[i], src, src + nr);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * text_poke_early - Update instructions on a live kernel at boot time
+ *
+ * When you use this code to patch more than one byte of an instruction
+ * you need to make sure that other CPUs cannot execute this code in parallel.
+ * Also no thread must be currently preempted in the middle of these
+ * instructions. And on the local CPU you need to be protected again NMI or MCE
+ * handlers seeing an inconsistent instruction while you patch.
+ */
+static void *__init_or_module text_poke_early(union loongarch_instruction *insn,
+ union loongarch_instruction *buf, unsigned int nr)
+{
+ int i;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ for (i = 0; i < nr; i++)
+ insn[i].word = buf[i].word;
+
+ local_irq_restore(flags);
+
+ wbflush();
+ flush_icache_range((unsigned long)insn, (unsigned long)(insn + nr));
+
+ return insn;
+}
+
+/*
+ * Replace instructions with better alternatives for this CPU type. This runs
+ * before SMP is initialized to avoid SMP problems with self modifying code.
+ * This implies that asymmetric systems where APs have less capabilities than
+ * the boot processor are not handled. Tough. Make sure you disable such
+ * features by hand.
+ */
+void __init_or_module apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+{
+ struct alt_instr *a;
+ unsigned int nr_instr, nr_repl, nr_insnbuf;
+ union loongarch_instruction *instr, *replacement;
+ union loongarch_instruction insnbuf[MAX_PATCH_SIZE];
+
+ DPRINTK("alt table %px, -> %px", start, end);
+ /*
+ * The scan order should be from start to end. A later scanned
+ * alternative code can overwrite previously scanned alternative code.
+ * Some kernel functions (e.g. memcpy, memset, etc) use this order to
+ * patch code.
+ *
+ * So be careful if you want to change the scan order to any other
+ * order.
+ */
+ for (a = start; a < end; a++) {
+ nr_insnbuf = 0;
+
+ instr = (void *)&a->instr_offset + a->instr_offset;
+ replacement = (void *)&a->replace_offset + a->replace_offset;
+
+ BUG_ON(a->instrlen > sizeof(insnbuf));
+ BUG_ON(a->instrlen & 0x3);
+ BUG_ON(a->replacementlen & 0x3);
+
+ nr_instr = a->instrlen / LOONGARCH_INSN_SIZE;
+ nr_repl = a->replacementlen / LOONGARCH_INSN_SIZE;
+
+ if (!cpu_has(a->feature)) {
+ DPRINTK("feat not exist: %d, old: (%px len: %d), repl: (%px, len: %d)",
+ a->feature, instr, a->instrlen,
+ replacement, a->replacementlen);
+
+ continue;
+ }
+
+ DPRINTK("feat: %d, old: (%px len: %d), repl: (%px, len: %d)",
+ a->feature, instr, a->instrlen,
+ replacement, a->replacementlen);
+
+ DUMP_WORDS(instr, nr_instr, "%px: old_insn: ", instr);
+ DUMP_WORDS(replacement, nr_repl, "%px: rpl_insn: ", replacement);
+
+ copy_alt_insns(insnbuf, instr, replacement, nr_repl);
+ nr_insnbuf = nr_repl;
+
+ if (nr_instr > nr_repl) {
+ add_nops(insnbuf + nr_repl, nr_instr - nr_repl);
+ nr_insnbuf += nr_instr - nr_repl;
+ }
+ DUMP_WORDS(insnbuf, nr_insnbuf, "%px: final_insn: ", instr);
+
+ text_poke_early(instr, insnbuf, nr_insnbuf);
+ }
+}
+
+void __init alternative_instructions(void)
+{
+ apply_alternatives(__alt_instructions, __alt_instructions_end);
+
+ alternatives_patched = 1;
+}