#include <asm/insn.h>
#include <asm/io.h>
#include <asm/fixmap.h>
+#include <asm/paravirt.h>
int __read_mostly alternatives_patched;
} \
} while (0)
-/*
- * Each GENERIC_NOPX is of X bytes, and defined as an array of bytes
- * that correspond to that nop. Getting from one nop to the next, we
- * add to the array the offset that is equal to the sum of all sizes of
- * nops preceding the one we are after.
- *
- * Note: The GENERIC_NOP5_ATOMIC is at the end, as it breaks the
- * nice symmetry of sizes of the previous nops.
- */
-#if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64)
-static const unsigned char intelnops[] =
-{
- GENERIC_NOP1,
- GENERIC_NOP2,
- GENERIC_NOP3,
- GENERIC_NOP4,
- GENERIC_NOP5,
- GENERIC_NOP6,
- GENERIC_NOP7,
- GENERIC_NOP8,
- GENERIC_NOP5_ATOMIC
-};
-static const unsigned char * const intel_nops[ASM_NOP_MAX+2] =
+const unsigned char x86nops[] =
{
- NULL,
- intelnops,
- intelnops + 1,
- intelnops + 1 + 2,
- intelnops + 1 + 2 + 3,
- intelnops + 1 + 2 + 3 + 4,
- intelnops + 1 + 2 + 3 + 4 + 5,
- intelnops + 1 + 2 + 3 + 4 + 5 + 6,
- intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
- intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
+ BYTES_NOP1,
+ BYTES_NOP2,
+ BYTES_NOP3,
+ BYTES_NOP4,
+ BYTES_NOP5,
+ BYTES_NOP6,
+ BYTES_NOP7,
+ BYTES_NOP8,
};
-#endif
-#ifdef K8_NOP1
-static const unsigned char k8nops[] =
-{
- K8_NOP1,
- K8_NOP2,
- K8_NOP3,
- K8_NOP4,
- K8_NOP5,
- K8_NOP6,
- K8_NOP7,
- K8_NOP8,
- K8_NOP5_ATOMIC
-};
-static const unsigned char * const k8_nops[ASM_NOP_MAX+2] =
+const unsigned char * const x86_nops[ASM_NOP_MAX+1] =
{
NULL,
- k8nops,
- k8nops + 1,
- k8nops + 1 + 2,
- k8nops + 1 + 2 + 3,
- k8nops + 1 + 2 + 3 + 4,
- k8nops + 1 + 2 + 3 + 4 + 5,
- k8nops + 1 + 2 + 3 + 4 + 5 + 6,
- k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
- k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
+ x86nops,
+ x86nops + 1,
+ x86nops + 1 + 2,
+ x86nops + 1 + 2 + 3,
+ x86nops + 1 + 2 + 3 + 4,
+ x86nops + 1 + 2 + 3 + 4 + 5,
+ x86nops + 1 + 2 + 3 + 4 + 5 + 6,
+ x86nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
};
-#endif
-
-#if defined(K7_NOP1) && !defined(CONFIG_X86_64)
-static const unsigned char k7nops[] =
-{
- K7_NOP1,
- K7_NOP2,
- K7_NOP3,
- K7_NOP4,
- K7_NOP5,
- K7_NOP6,
- K7_NOP7,
- K7_NOP8,
- K7_NOP5_ATOMIC
-};
-static const unsigned char * const k7_nops[ASM_NOP_MAX+2] =
-{
- NULL,
- k7nops,
- k7nops + 1,
- k7nops + 1 + 2,
- k7nops + 1 + 2 + 3,
- k7nops + 1 + 2 + 3 + 4,
- k7nops + 1 + 2 + 3 + 4 + 5,
- k7nops + 1 + 2 + 3 + 4 + 5 + 6,
- k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
- k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
-};
-#endif
-
-#ifdef P6_NOP1
-static const unsigned char p6nops[] =
-{
- P6_NOP1,
- P6_NOP2,
- P6_NOP3,
- P6_NOP4,
- P6_NOP5,
- P6_NOP6,
- P6_NOP7,
- P6_NOP8,
- P6_NOP5_ATOMIC
-};
-static const unsigned char * const p6_nops[ASM_NOP_MAX+2] =
-{
- NULL,
- p6nops,
- p6nops + 1,
- p6nops + 1 + 2,
- p6nops + 1 + 2 + 3,
- p6nops + 1 + 2 + 3 + 4,
- p6nops + 1 + 2 + 3 + 4 + 5,
- p6nops + 1 + 2 + 3 + 4 + 5 + 6,
- p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
- p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8,
-};
-#endif
-
-/* Initialize these to a safe default */
-#ifdef CONFIG_X86_64
-const unsigned char * const *ideal_nops = p6_nops;
-#else
-const unsigned char * const *ideal_nops = intel_nops;
-#endif
-
-void __init arch_init_ideal_nops(void)
-{
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_INTEL:
- /*
- * Due to a decoder implementation quirk, some
- * specific Intel CPUs actually perform better with
- * the "k8_nops" than with the SDM-recommended NOPs.
- */
- if (boot_cpu_data.x86 == 6 &&
- boot_cpu_data.x86_model >= 0x0f &&
- boot_cpu_data.x86_model != 0x1c &&
- boot_cpu_data.x86_model != 0x26 &&
- boot_cpu_data.x86_model != 0x27 &&
- boot_cpu_data.x86_model < 0x30) {
- ideal_nops = k8_nops;
- } else if (boot_cpu_has(X86_FEATURE_NOPL)) {
- ideal_nops = p6_nops;
- } else {
-#ifdef CONFIG_X86_64
- ideal_nops = k8_nops;
-#else
- ideal_nops = intel_nops;
-#endif
- }
- break;
-
- case X86_VENDOR_HYGON:
- ideal_nops = p6_nops;
- return;
-
- case X86_VENDOR_AMD:
- if (boot_cpu_data.x86 > 0xf) {
- ideal_nops = p6_nops;
- return;
- }
-
- fallthrough;
-
- default:
-#ifdef CONFIG_X86_64
- ideal_nops = k8_nops;
-#else
- if (boot_cpu_has(X86_FEATURE_K8))
- ideal_nops = k8_nops;
- else if (boot_cpu_has(X86_FEATURE_K7))
- ideal_nops = k7_nops;
- else
- ideal_nops = intel_nops;
-#endif
- }
-}
/* Use this to add nops to a buffer, then text_poke the whole buffer. */
static void __init_or_module add_nops(void *insns, unsigned int len)
unsigned int noplen = len;
if (noplen > ASM_NOP_MAX)
noplen = ASM_NOP_MAX;
- memcpy(insns, ideal_nops[noplen], noplen);
+ memcpy(insns, x86_nops[noplen], noplen);
insns += noplen;
len -= noplen;
}
static void __init_or_module noinline optimize_nops(struct alt_instr *a, u8 *instr)
{
unsigned long flags;
- int i;
+ struct insn insn;
+ int nop, i = 0;
+
+ /*
+ * Jump over the non-NOP insns, the remaining bytes must be single-byte
+ * NOPs, optimize them.
+ */
+ for (;;) {
+ if (insn_decode_kernel(&insn, &instr[i]))
+ return;
+
+ if (insn.length == 1 && insn.opcode.bytes[0] == 0x90)
+ break;
+
+ if ((i += insn.length) >= a->instrlen)
+ return;
+ }
- for (i = 0; i < a->padlen; i++) {
- if (instr[i] != 0x90)
+ for (nop = i; i < a->instrlen; i++) {
+ if (WARN_ONCE(instr[i] != 0x90, "Not a NOP at 0x%px\n", &instr[i]))
return;
}
local_irq_save(flags);
- add_nops(instr + (a->instrlen - a->padlen), a->padlen);
+ add_nops(instr + nop, i - nop);
local_irq_restore(flags);
DUMP_BYTES(instr, a->instrlen, "%px: [%d:%d) optimized NOPs: ",
- instr, a->instrlen - a->padlen, a->padlen);
+ instr, nop, a->instrlen);
}
/*
*/
for (a = start; a < end; a++) {
int insn_buff_sz = 0;
+ /* Mask away "NOT" flag bit for feature to test. */
+ u16 feature = a->cpuid & ~ALTINSTR_FLAG_INV;
instr = (u8 *)&a->instr_offset + a->instr_offset;
replacement = (u8 *)&a->repl_offset + a->repl_offset;
BUG_ON(a->instrlen > sizeof(insn_buff));
- BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
- if (!boot_cpu_has(a->cpuid)) {
- if (a->padlen > 1)
- optimize_nops(a, instr);
+ BUG_ON(feature >= (NCAPINTS + NBUGINTS) * 32);
- continue;
- }
+ /*
+ * Patch if either:
+ * - feature is present
+ * - feature not present but ALTINSTR_FLAG_INV is set to mean,
+ * patch if feature is *NOT* present.
+ */
+ if (!boot_cpu_has(feature) == !(a->cpuid & ALTINSTR_FLAG_INV))
+ goto next;
- DPRINTK("feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d), pad: %d",
- a->cpuid >> 5,
- a->cpuid & 0x1f,
+ DPRINTK("feat: %s%d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d)",
+ (a->cpuid & ALTINSTR_FLAG_INV) ? "!" : "",
+ feature >> 5,
+ feature & 0x1f,
instr, instr, a->instrlen,
- replacement, a->replacementlen, a->padlen);
+ replacement, a->replacementlen);
DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr);
DUMP_BYTES(replacement, a->replacementlen, "%px: rpl_insn: ", replacement);
if (a->replacementlen && is_jmp(replacement[0]))
recompute_jump(a, instr, replacement, insn_buff);
- if (a->instrlen > a->replacementlen) {
- add_nops(insn_buff + a->replacementlen,
- a->instrlen - a->replacementlen);
- insn_buff_sz += a->instrlen - a->replacementlen;
- }
+ for (; insn_buff_sz < a->instrlen; insn_buff_sz++)
+ insn_buff[insn_buff_sz] = 0x90;
+
DUMP_BYTES(insn_buff, insn_buff_sz, "%px: final_insn: ", instr);
text_poke_early(instr, insn_buff, insn_buff_sz);
+
+next:
+ optimize_nops(a, instr);
}
}
BUG_ON(p->len > MAX_PATCH_LEN);
/* prep the buffer with the original instructions */
memcpy(insn_buff, p->instr, p->len);
- used = pv_ops.init.patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
+ used = paravirt_patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
BUG_ON(used > p->len);
* patching.
*/
+ /*
+ * Paravirt patching and alternative patching can be combined to
+ * replace a function call with a short direct code sequence (e.g.
+ * by setting a constant return value instead of doing that in an
+ * external function).
+ * In order to make this work the following sequence is required:
+ * 1. set (artificial) features depending on used paravirt
+ * functions which can later influence alternative patching
+ * 2. apply paravirt patching (generally replacing an indirect
+ * function call with a direct one)
+ * 3. apply alternative patching (e.g. replacing a direct function
+ * call with a custom code sequence)
+ * Doing paravirt patching after alternative patching would clobber
+ * the optimization of the custom code with a function call again.
+ */
+ paravirt_set_cap();
+
+ /*
+ * First patch paravirt functions, such that we overwrite the indirect
+ * call with the direct call.
+ */
+ apply_paravirt(__parainstructions, __parainstructions_end);
+
+ /*
+ * Then patch alternatives, such that those paravirt calls that are in
+ * alternatives can be overwritten by their immediate fragments.
+ */
apply_alternatives(__alt_instructions, __alt_instructions_end);
#ifdef CONFIG_SMP
}
#endif
- apply_paravirt(__parainstructions, __parainstructions_end);
-
restart_nmi();
alternatives_patched = 1;
}
const void *opcode, size_t len, const void *emulate)
{
struct insn insn;
+ int ret;
memcpy((void *)tp->text, opcode, len);
if (!emulate)
emulate = opcode;
- kernel_insn_init(&insn, emulate, MAX_INSN_SIZE);
- insn_get_length(&insn);
+ ret = insn_decode_kernel(&insn, emulate);
- BUG_ON(!insn_complete(&insn));
+ BUG_ON(ret < 0);
BUG_ON(len != insn.length);
tp->rel_addr = addr - (void *)_stext;
default: /* assume NOP */
switch (len) {
case 2: /* NOP2 -- emulate as JMP8+0 */
- BUG_ON(memcmp(emulate, ideal_nops[len], len));
+ BUG_ON(memcmp(emulate, x86_nops[len], len));
tp->opcode = JMP8_INSN_OPCODE;
tp->rel32 = 0;
break;
case 5: /* NOP5 -- emulate as JMP32+0 */
- BUG_ON(memcmp(emulate, ideal_nops[NOP_ATOMIC5], len));
+ BUG_ON(memcmp(emulate, x86_nops[len], len));
tp->opcode = JMP32_INSN_OPCODE;
tp->rel32 = 0;
break;
projects / platform / kernel / linux-starfive.git / blobdiff