From 125f0b7d24216f37a9683b3899fa45101090f098 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 21 Jan 2021 15:29:35 -0600 Subject: [PATCH] x86/power: Move restore_registers() to top of the file Because restore_registers() is page-aligned, the assembler inexplicably adds an unreachable jump from after the end of the previous function to the beginning of restore_registers(). That confuses objtool, understandably. It also creates significant text fragmentation. As a result, most of the object file is wasted text (nops). Move restore_registers() to the beginning of the file to both prevent the text fragmentation and avoid the dead jump instruction. $ size /tmp/hibernate_asm_64.before.o /tmp/hibernate_asm_64.after.o text data bss dec hex filename 4415 0 0 4415 113f /tmp/hibernate_asm_64.before.o 524 0 0 524 20c /tmp/hibernate_asm_64.after.o Cc: "Rafael J. Wysocki" Cc: Pavel Machek Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/8c7f634201d26453d73fe55032cbbdc05d004387.1611263462.git.jpoimboe@redhat.com --- arch/x86/power/hibernate_asm_64.S | 92 +++++++++++++++---------------- 1 file changed, 46 insertions(+), 46 deletions(-) diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S index 715509d94fa34..91c4602d2b5d6 100644 --- a/arch/x86/power/hibernate_asm_64.S +++ b/arch/x86/power/hibernate_asm_64.S @@ -23,6 +23,52 @@ #include #include + /* code below belongs to the image kernel */ + .align PAGE_SIZE +SYM_FUNC_START(restore_registers) + /* go back to the original page tables */ + movq %r9, %cr3 + + /* Flush TLB, including "global" things (vmalloc) */ + movq mmu_cr4_features(%rip), %rax + movq %rax, %rdx + andq $~(X86_CR4_PGE), %rdx + movq %rdx, %cr4; # turn off PGE + movq %cr3, %rcx; # flush TLB + movq %rcx, %cr3 + movq %rax, %cr4; # turn PGE back on + + /* We don't restore %rax, it must be 0 anyway */ + movq $saved_context, %rax + movq pt_regs_sp(%rax), %rsp + movq pt_regs_bp(%rax), %rbp + movq pt_regs_si(%rax), %rsi + movq pt_regs_di(%rax), %rdi + movq pt_regs_bx(%rax), %rbx + movq pt_regs_cx(%rax), %rcx + movq pt_regs_dx(%rax), %rdx + movq pt_regs_r8(%rax), %r8 + movq pt_regs_r9(%rax), %r9 + movq pt_regs_r10(%rax), %r10 + movq pt_regs_r11(%rax), %r11 + movq pt_regs_r12(%rax), %r12 + movq pt_regs_r13(%rax), %r13 + movq pt_regs_r14(%rax), %r14 + movq pt_regs_r15(%rax), %r15 + pushq pt_regs_flags(%rax) + popfq + + /* Saved in save_processor_state. */ + lgdt saved_context_gdt_desc(%rax) + + xorl %eax, %eax + + /* tell the hibernation core that we've just restored the memory */ + movq %rax, in_suspend(%rip) + + ret +SYM_FUNC_END(restore_registers) + SYM_FUNC_START(swsusp_arch_suspend) movq $saved_context, %rax movq %rsp, pt_regs_sp(%rax) @@ -102,49 +148,3 @@ SYM_CODE_START(core_restore_code) ANNOTATE_RETPOLINE_SAFE jmpq *%r8 SYM_CODE_END(core_restore_code) - - /* code below belongs to the image kernel */ - .align PAGE_SIZE -SYM_FUNC_START(restore_registers) - /* go back to the original page tables */ - movq %r9, %cr3 - - /* Flush TLB, including "global" things (vmalloc) */ - movq mmu_cr4_features(%rip), %rax - movq %rax, %rdx - andq $~(X86_CR4_PGE), %rdx - movq %rdx, %cr4; # turn off PGE - movq %cr3, %rcx; # flush TLB - movq %rcx, %cr3 - movq %rax, %cr4; # turn PGE back on - - /* We don't restore %rax, it must be 0 anyway */ - movq $saved_context, %rax - movq pt_regs_sp(%rax), %rsp - movq pt_regs_bp(%rax), %rbp - movq pt_regs_si(%rax), %rsi - movq pt_regs_di(%rax), %rdi - movq pt_regs_bx(%rax), %rbx - movq pt_regs_cx(%rax), %rcx - movq pt_regs_dx(%rax), %rdx - movq pt_regs_r8(%rax), %r8 - movq pt_regs_r9(%rax), %r9 - movq pt_regs_r10(%rax), %r10 - movq pt_regs_r11(%rax), %r11 - movq pt_regs_r12(%rax), %r12 - movq pt_regs_r13(%rax), %r13 - movq pt_regs_r14(%rax), %r14 - movq pt_regs_r15(%rax), %r15 - pushq pt_regs_flags(%rax) - popfq - - /* Saved in save_processor_state. */ - lgdt saved_context_gdt_desc(%rax) - - xorl %eax, %eax - - /* tell the hibernation core that we've just restored the memory */ - movq %rax, in_suspend(%rip) - - ret -SYM_FUNC_END(restore_registers) -- 2.39.5