From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Sami Tolvanen <samitolvanen@google.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
Kees Cook <keescook@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
Miroslav Benes <mbenes@suse.cz>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Pavel Machek <pavel@ucw.cz>
Subject: [PATCH 20/21] x86/power: Move restore_registers() to top of the file
Date: Thu, 14 Jan 2021 13:40:16 -0600 [thread overview]
Message-ID: <66baa19ceda840fc89a3bed8e0549db1184685a5.1610652862.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1610652862.git.jpoimboe@redhat.com>
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" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Josh Poimboeuf <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 24d971911c9d..4ca6d68b0293 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -23,6 +23,52 @@
#include <asm/frame.h>
#include <asm/nospec-branch.h>
+ /* 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)
@@ -100,49 +146,3 @@ SYM_CODE_START(core_restore_code)
/* jump to the restore_registers address from the image header */
JMP_NOSPEC 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)
--
2.29.2
next prev parent reply other threads:[~2021-01-14 19:43 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 19:39 [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 01/21] objtool: Fix seg fault in BT_FUNC() with fake jump Josh Poimboeuf
2021-01-14 20:04 ` Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 02/21] objtool: Fix error handling for STD/CLD warnings Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 03/21] objtool: Fix retpoline detection in asm code Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 04/21] objtool: Fix ".cold" section suffix check for newer versions of GCC Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 05/21] objtool: Support retpoline jump detection for vmlinux.o Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 06/21] x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub Josh Poimboeuf
2021-01-14 20:42 ` Steven Rostedt
2021-01-14 19:40 ` [PATCH 07/21] objtool: Assume only ELF functions do sibling calls Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 08/21] objtool: Add asm version of STACK_FRAME_NON_STANDARD Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 09/21] objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNC Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 10/21] objtool: Add xen_start_kernel() to noreturn list Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 11/21] objtool: Move unsuffixed symbol conversion to a helper function Josh Poimboeuf
2021-01-14 20:55 ` [PATCH v1.1 " Josh Poimboeuf
2021-01-14 21:30 ` Sedat Dilek
2021-01-14 19:40 ` [PATCH 12/21] objtool: Add CONFIG_CFI_CLANG support Josh Poimboeuf
2021-01-14 20:49 ` Sami Tolvanen
2021-01-14 20:52 ` Josh Poimboeuf
2021-01-14 20:56 ` [PATCH v1.1 " Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 13/21] x86/xen: Support objtool validation in xen-asm.S Josh Poimboeuf
2021-01-15 0:31 ` boris.ostrovsky
2021-01-14 19:40 ` [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in xen-head.S Josh Poimboeuf
2021-01-15 0:32 ` boris.ostrovsky
2021-01-15 5:17 ` Jürgen Groß
2021-01-15 19:46 ` Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 15/21] x86/xen/pvh: Convert indirect jump to retpoline Josh Poimboeuf
2021-01-15 0:33 ` boris.ostrovsky
2021-01-15 5:24 ` Jürgen Groß
2021-01-15 15:08 ` Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 16/21] x86/ftrace: Support objtool vmlinux.o validation in ftrace_64.S Josh Poimboeuf
2021-01-14 20:42 ` Steven Rostedt
2021-01-14 19:40 ` [PATCH 17/21] x86/acpi: Convert indirect jump to retpoline Josh Poimboeuf
2021-01-14 22:59 ` Andrew Cooper
2021-01-14 23:47 ` Josh Poimboeuf
2021-01-15 0:54 ` Andrew Cooper
2021-01-14 19:40 ` [PATCH 18/21] x86/acpi: Support objtool validation in wakeup_64.S Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 19/21] x86/power: Convert indirect jumps to retpolines Josh Poimboeuf
2021-01-14 19:40 ` Josh Poimboeuf [this message]
2021-01-14 19:40 ` [PATCH 21/21] x86/power: Support objtool validation in hibernate_asm_64.S Josh Poimboeuf
2021-01-15 0:41 ` [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support Sami Tolvanen
2021-01-15 0:49 ` Nick Desaulniers
2021-01-15 19:52 ` Josh Poimboeuf
2021-01-15 20:19 ` Sedat Dilek
2021-01-15 20:59 ` Josh Poimboeuf
2021-01-15 21:01 ` Sedat Dilek
2021-01-18 17:22 ` Josh Poimboeuf
2021-01-19 21:29 ` Nick Desaulniers
2021-01-20 15:37 ` Josh Poimboeuf
2021-01-15 4:51 ` Sedat Dilek
2021-01-15 5:18 ` Sedat Dilek
2021-01-15 15:30 ` Sedat Dilek
2021-01-15 18:54 ` Sedat Dilek
2021-01-15 19:28 ` Josh Poimboeuf
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