Messages in this thread Patch in this message | | | Date | Thu, 24 Jun 2021 11:41:13 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v2 14/24] x86/xen: Make read_cr2() noinstr |
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vmlinux.o: warning: objtool: pv_ops[41]: native_read_cr2 vmlinux.o: warning: objtool: pv_ops[41]: xen_read_cr2 vmlinux.o: warning: objtool: pv_ops[41]: xen_read_cr2_direct vmlinux.o: warning: objtool: exc_double_fault()+0x15: call to pv_ops[41]() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/include/asm/paravirt.h | 2 +- arch/x86/kernel/paravirt.c | 7 ++++++- arch/x86/xen/xen-asm.S | 2 ++ 3 files changed, 9 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -133,7 +133,7 @@ static inline void write_cr0(unsigned lo PVOP_VCALL1(cpu.write_cr0, x); } -static inline unsigned long read_cr2(void) +static __always_inline unsigned long read_cr2(void) { return PVOP_ALT_CALLEE0(unsigned long, mmu.read_cr2, "mov %%cr2, %%rax;", --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -238,6 +238,11 @@ struct pv_info pv_info = { /* 64-bit pagetable entries */ #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) +static noinstr unsigned long pv_native_read_cr2(void) +{ + return native_read_cr2(); +} + struct paravirt_patch_template pv_ops = { /* Cpu ops. */ .cpu.io_delay = native_io_delay, @@ -298,7 +303,7 @@ struct paravirt_patch_template pv_ops = .mmu.exit_mmap = paravirt_nop, #ifdef CONFIG_PARAVIRT_XXL - .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2), + .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2), .mmu.write_cr2 = native_write_cr2, .mmu.read_cr3 = __native_read_cr3, .mmu.write_cr3 = native_write_cr3, --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -102,6 +102,7 @@ SYM_FUNC_START(check_events) ret SYM_FUNC_END(check_events) +.pushsection .noinstr.text, "ax" SYM_FUNC_START(xen_read_cr2) FRAME_BEGIN _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX @@ -116,6 +117,7 @@ SYM_FUNC_START(xen_read_cr2_direct) FRAME_END ret SYM_FUNC_END(xen_read_cr2_direct); +.popsection .macro xen_pv_trap name SYM_CODE_START(xen_\name)
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