diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/static_call.c | 98 | ||||
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 1 |
6 files changed, 110 insertions, 1 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index e77261db2391..de09af019e23 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -68,6 +68,7 @@ obj-y += tsc.o tsc_msr.o io_delay.o rtc.o obj-y += pci-iommu_table.o obj-y += resource.o obj-y += irqflags.o +obj-y += static_call.o obj-y += process.o obj-y += fpu/ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index cdaab30880b9..4adbe65afe23 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1103,6 +1103,10 @@ noinstr int poke_int3_handler(struct pt_regs *regs) */ goto out_put; + case RET_INSN_OPCODE: + int3_emulate_ret(regs); + break; + case CALL_INSN_OPCODE: int3_emulate_call(regs, (long)ip + tp->rel32); break; @@ -1277,6 +1281,7 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr, switch (tp->opcode) { case INT3_INSN_OPCODE: + case RET_INSN_OPCODE: break; case CALL_INSN_OPCODE: diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 40f380461e6d..c068e21c2c40 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -18,6 +18,7 @@ #include <linux/ftrace.h> #include <linux/frame.h> #include <linux/pgtable.h> +#include <linux/static_call.h> #include <asm/text-patching.h> #include <asm/cacheflush.h> @@ -210,7 +211,8 @@ static int copy_optimized_instructions(u8 *dest, u8 *src, u8 *real) /* Check whether the address range is reserved */ if (ftrace_text_reserved(src, src + len - 1) || alternatives_text_reserved(src, src + len - 1) || - jump_label_text_reserved(src, src + len - 1)) + jump_label_text_reserved(src, src + len - 1) || + static_call_text_reserved(src, src + len - 1)) return -EBUSY; return len; diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d41be0df72f8..fa16b906ea3f 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -19,6 +19,7 @@ #include <linux/hugetlb.h> #include <linux/tboot.h> #include <linux/usb/xhci-dbgp.h> +#include <linux/static_call.h> #include <uapi/linux/mount.h> @@ -849,6 +850,7 @@ void __init setup_arch(char **cmdline_p) early_cpu_init(); arch_init_ideal_nops(); jump_label_init(); + static_call_init(); early_ioremap_init(); setup_olpc_ofw_pgd(); diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c new file mode 100644 index 000000000000..ca9a380d9c0b --- /dev/null +++ b/arch/x86/kernel/static_call.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/static_call.h> +#include <linux/memory.h> +#include <linux/bug.h> +#include <asm/text-patching.h> + +enum insn_type { + CALL = 0, /* site call */ + NOP = 1, /* site cond-call */ + JMP = 2, /* tramp / site tail-call */ + RET = 3, /* tramp / site cond-tail-call */ +}; + +static void __ref __static_call_transform(void *insn, enum insn_type type, void *func) +{ + int size = CALL_INSN_SIZE; + const void *code; + + switch (type) { + case CALL: + code = text_gen_insn(CALL_INSN_OPCODE, insn, func); + break; + + case NOP: + code = ideal_nops[NOP_ATOMIC5]; + break; + + case JMP: + code = text_gen_insn(JMP32_INSN_OPCODE, insn, func); + break; + + case RET: + code = text_gen_insn(RET_INSN_OPCODE, insn, func); + size = RET_INSN_SIZE; + break; + } + + if (memcmp(insn, code, size) == 0) + return; + + if (unlikely(system_state == SYSTEM_BOOTING)) + return text_poke_early(insn, code, size); + + text_poke_bp(insn, code, size, NULL); +} + +static void __static_call_validate(void *insn, bool tail) +{ + u8 opcode = *(u8 *)insn; + + if (tail) { + if (opcode == JMP32_INSN_OPCODE || + opcode == RET_INSN_OPCODE) + return; + } else { + if (opcode == CALL_INSN_OPCODE || + !memcmp(insn, ideal_nops[NOP_ATOMIC5], 5)) + return; + } + + /* + * If we ever trigger this, our text is corrupt, we'll probably not live long. + */ + WARN_ONCE(1, "unexpected static_call insn opcode 0x%x at %pS\n", opcode, insn); +} + +static inline enum insn_type __sc_insn(bool null, bool tail) +{ + /* + * Encode the following table without branches: + * + * tail null insn + * -----+-------+------ + * 0 | 0 | CALL + * 0 | 1 | NOP + * 1 | 0 | JMP + * 1 | 1 | RET + */ + return 2*tail + null; +} + +void arch_static_call_transform(void *site, void *tramp, void *func, bool tail) +{ + mutex_lock(&text_mutex); + + if (tramp) { + __static_call_validate(tramp, true); + __static_call_transform(tramp, __sc_insn(!func, true), func); + } + + if (IS_ENABLED(CONFIG_HAVE_STATIC_CALL_INLINE) && site) { + __static_call_validate(site, tail); + __static_call_transform(site, __sc_insn(!func, tail), func); + } + + mutex_unlock(&text_mutex); +} +EXPORT_SYMBOL_GPL(arch_static_call_transform); diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 45d72447df84..bf9e0adb5b7e 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -136,6 +136,7 @@ SECTIONS ENTRY_TEXT ALIGN_ENTRY_TEXT_END SOFTIRQENTRY_TEXT + STATIC_CALL_TEXT *(.fixup) *(.gnu.warning) |