Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH v2 3/9] x86/paravirt: Replace paravirt patches with data | Date | Fri, 29 Mar 2019 17:47:37 -0700 |
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From: Andi Kleen <ak@linux.intel.com>
For LTO all top level assembler statements need to be global because LTO might put it into a different assembler file than the referencing C code.
To avoid making all the paravirt patch snippets global replace them with data containing the patch instructions. Since these are unlikely to change this shouldn't be a significant maintenance burden.
Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andi Kleen <ak@linux.intel.com> --- arch/x86/include/asm/paravirt_types.h | 6 +--- arch/x86/kernel/paravirt_patch_32.c | 33 +++++++++++---------- arch/x86/kernel/paravirt_patch_64.c | 42 +++++++++++++++------------ 3 files changed, 42 insertions(+), 39 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 2474e434a6f7..bb13e79d4344 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -367,12 +367,8 @@ extern struct paravirt_patch_template pv_ops; #define paravirt_alt(insn_string) \ _paravirt_alt(insn_string, "%c[paravirt_typenum]", "%c[paravirt_clobber]") -/* Simple instruction patching code. */ -#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t" - #define DEF_NATIVE(ops, name, code) \ - __visible extern const char start_##ops##_##name[], end_##ops##_##name[]; \ - asm(NATIVE_LABEL("start_", ops, name) code NATIVE_LABEL("end_", ops, name)) + const char start_##ops##_##name[] = code unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len); unsigned paravirt_patch_default(u8 type, void *insnbuf, diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c index de138d3912e4..9a649026d74c 100644 --- a/arch/x86/kernel/paravirt_patch_32.c +++ b/arch/x86/kernel/paravirt_patch_32.c @@ -2,14 +2,14 @@ #include <asm/paravirt.h> #ifdef CONFIG_PARAVIRT_XXL -DEF_NATIVE(irq, irq_disable, "cli"); -DEF_NATIVE(irq, irq_enable, "sti"); -DEF_NATIVE(irq, restore_fl, "push %eax; popf"); -DEF_NATIVE(irq, save_fl, "pushf; pop %eax"); -DEF_NATIVE(cpu, iret, "iret"); -DEF_NATIVE(mmu, read_cr2, "mov %cr2, %eax"); -DEF_NATIVE(mmu, write_cr3, "mov %eax, %cr3"); -DEF_NATIVE(mmu, read_cr3, "mov %cr3, %eax"); +static const unsigned char patch_irq_irq_disable[] = { 0xfa }; /* cli */ +static const unsigned char patch_irq_irq_enable[] = { 0xfb }; /* sti */ +static const unsigned char patch_irq_restore_fl[] = { 0x50, 0x9d }; /* push %eax; popf */ +static const unsigned char patch_irq_save_fl[] = { 0x9c, 0x58 }; /* pushf; pop %eax */ +static const unsigned char patch_cpu_iret[] = { 0xcf }; /* iret */ +static const unsigned char patch_mmu_read_cr2[] = { 0x0f, 0x20, 0xd0 }; /* mov %cr2, %eax */ +static const unsigned char patch_mmu_write_cr3[] = { 0x0f, 0x22, 0xd8 };/* mov %eax, %cr3 */ +static const unsigned char patch_mmu_read_cr3[] = { 0x0f, 0x20, 0xd8 }; /* mov %cr3, %eax */ unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len) { @@ -19,8 +19,8 @@ unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len) #endif #if defined(CONFIG_PARAVIRT_SPINLOCKS) -DEF_NATIVE(lock, queued_spin_unlock, "movb $0, (%eax)"); -DEF_NATIVE(lock, vcpu_is_preempted, "xor %eax, %eax"); +static const unsigned char patch_lock_queued_spin_unlock[] = { 0xc6, 0x00, 0x00 }; /* movb $0, (%eax) */ +static const unsigned char patch_lock_vcpu_is_preempted[] = { 0x31, 0xc0 }; /* xor %eax, %eax */ #endif extern bool pv_is_native_spin_unlock(void); @@ -30,7 +30,8 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len) { #define PATCH_SITE(ops, x) \ case PARAVIRT_PATCH(ops.x): \ - return paravirt_patch_insns(ibuf, len, start_##ops##_##x, end_##ops##_##x) + return paravirt_patch_insns(ibuf, len, \ + patch_##ops##_##x, patch_##ops##_##x+sizeof(patch_##ops##_x)); switch (type) { #ifdef CONFIG_PARAVIRT_XXL @@ -47,15 +48,17 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len) case PARAVIRT_PATCH(lock.queued_spin_unlock): if (pv_is_native_spin_unlock()) return paravirt_patch_insns(ibuf, len, - start_lock_queued_spin_unlock, - end_lock_queued_spin_unlock); + patch_lock_queued_spin_unlock, + patch_lock_queued_spin_unlock + + sizeof(patch_lock_queued_spin_unlock)); break; case PARAVIRT_PATCH(lock.vcpu_is_preempted): if (pv_is_native_vcpu_is_preempted()) return paravirt_patch_insns(ibuf, len, - start_lock_vcpu_is_preempted, - end_lock_vcpu_is_preempted); + patch_lock_vcpu_is_preempted, + patch_lock_vcpu_is_preempted + + sizeof(patch_lock_vcpu_is_preempted)); break; #endif diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c index 9d9e04b31077..fce6f54665d3 100644 --- a/arch/x86/kernel/paravirt_patch_64.c +++ b/arch/x86/kernel/paravirt_patch_64.c @@ -4,29 +4,30 @@ #include <linux/stringify.h> #ifdef CONFIG_PARAVIRT_XXL -DEF_NATIVE(irq, irq_disable, "cli"); -DEF_NATIVE(irq, irq_enable, "sti"); -DEF_NATIVE(irq, restore_fl, "pushq %rdi; popfq"); -DEF_NATIVE(irq, save_fl, "pushfq; popq %rax"); -DEF_NATIVE(mmu, read_cr2, "movq %cr2, %rax"); -DEF_NATIVE(mmu, read_cr3, "movq %cr3, %rax"); -DEF_NATIVE(mmu, write_cr3, "movq %rdi, %cr3"); -DEF_NATIVE(cpu, wbinvd, "wbinvd"); +static const unsigned char patch_irq_irq_disable[] = { 0xfa }; /* cli */ +static const unsigned char patch_irq_irq_enable[] = { 0xfb }; /* sti */ +static const unsigned char patch_irq_restore_fl[] = { 0x50, 0x9d}; /* pushq %rdi; popfq */ +static const unsigned char patch_irq_save_fl[] = { 0x9c, 0x58 }; /* pushfq; popq %rax */ +static const unsigned char patch_mmu_read_cr2[] = { 0x0f, 0x20, 0xd0 }; /* movq %cr2, %rax */ +static const unsigned char patch_mmu_read_cr3[] = { 0x0f, 0x22, 0xd8 }; /* movq %cr3, %rax */ +static const unsigned char patch_mmu_write_cr3[] = { 0x0f, 0x22, 0xdf }; /* movq %rdi, %cr3 */ +static const unsigned char patch_cpu_wbinvd[] = { 0x0f, 0x09 }; /* wbinvd */ -DEF_NATIVE(cpu, usergs_sysret64, "swapgs; sysretq"); -DEF_NATIVE(cpu, swapgs, "swapgs"); -DEF_NATIVE(, mov64, "mov %rdi, %rax"); +static const unsigned char patch_cpu_usergs_sysret64[] = { 0x0f, 0x01, 0xf8, 0x48, 0x0f, 0x07 }; + /* swapgs; sysretq */ +static const unsigned char patch_cpu_swapgs[] = { 0x0f, 0x01, 0xf8 }; /* swapgs */ +static const unsigned char patch_mov64[] = { 0x48, 0x89, 0xf8 }; /* mov %rdi, %rax */ unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len) { return paravirt_patch_insns(insnbuf, len, - start__mov64, end__mov64); + start_mov64, start_mov64 + sizeof(start_mov64)); } #endif #if defined(CONFIG_PARAVIRT_SPINLOCKS) -DEF_NATIVE(lock, queued_spin_unlock, "movb $0, (%rdi)"); -DEF_NATIVE(lock, vcpu_is_preempted, "xor %eax, %eax"); +static const unsigned char patch_lock_queued_spin_unlock[] = { 0xc6, 0x07, 0x00}; /* movb $0, (%rdi) */ +static const unsigned char patch_lock_vcpu_is_preempted[] = { 0x31, 0xc0 }; /* xor %eax, %eax */ #endif extern bool pv_is_native_spin_unlock(void); @@ -36,7 +37,8 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len) { #define PATCH_SITE(ops, x) \ case PARAVIRT_PATCH(ops.x): \ - return paravirt_patch_insns(ibuf, len, start_##ops##_##x, end_##ops##_##x) + return paravirt_patch_insns(ibuf, len, start_##ops##_##x, \ + patch_##ops##_##x + sizeof(patch_##ops##_##x)); switch (type) { #ifdef CONFIG_PARAVIRT_XXL @@ -55,15 +57,17 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len) case PARAVIRT_PATCH(lock.queued_spin_unlock): if (pv_is_native_spin_unlock()) return paravirt_patch_insns(ibuf, len, - start_lock_queued_spin_unlock, - end_lock_queued_spin_unlock); + patch_lock_queued_spin_unlock, + patch_lock_queued_spin_unlock + + sizeof(patch_lock_queued_spin_unlock)); break; case PARAVIRT_PATCH(lock.vcpu_is_preempted): if (pv_is_native_vcpu_is_preempted()) return paravirt_patch_insns(ibuf, len, - start_lock_vcpu_is_preempted, - end_lock_vcpu_is_preempted); + patch_lock_vcpu_is_preempted, + patch_lock_vcpu_is_preempted + + sizeof(patch_lock_vcpu_is_preempted)); break; #endif -- 2.20.1
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