2021-05-10 17:47:24

by H. Peter Anvin

[permalink] [raw]
Subject: [RFC PATCH 1/6] x86/entry: unify definitions from calling.h and ptrace-abi.h

From: "H. Peter Anvin (Intel)" <[email protected]>

The register offsets in <asm/ptrace-abi.h> are duplicated in
entry/calling.h, but are formatted differently and therefore not
compatible. Use the version from <asm/ptrace-abi.h> consistently.

Signed-off-by: H. Peter Anvin (Intel) <[email protected]>
---
arch/x86/entry/calling.h | 36 +-----------------------------------
arch/x86/kernel/head_64.S | 6 +++---
2 files changed, 4 insertions(+), 38 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 07a9331d55e7..7436d4a74ecb 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -6,6 +6,7 @@
#include <asm/percpu.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
+#include <asm/ptrace-abi.h>

/*

@@ -62,41 +63,6 @@ For 32-bit we have the following conventions - kernel is built with
* for assembly code:
*/

-/* The layout forms the "struct pt_regs" on the stack: */
-/*
- * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
- * unless syscall needs a complete, fully filled "struct pt_regs".
- */
-#define R15 0*8
-#define R14 1*8
-#define R13 2*8
-#define R12 3*8
-#define RBP 4*8
-#define RBX 5*8
-/* These regs are callee-clobbered. Always saved on kernel entry. */
-#define R11 6*8
-#define R10 7*8
-#define R9 8*8
-#define R8 9*8
-#define RAX 10*8
-#define RCX 11*8
-#define RDX 12*8
-#define RSI 13*8
-#define RDI 14*8
-/*
- * On syscall entry, this is syscall#. On CPU exception, this is error code.
- * On hw interrupt, it's IRQ number:
- */
-#define ORIG_RAX 15*8
-/* Return frame for iretq */
-#define RIP 16*8
-#define CS 17*8
-#define EFLAGS 18*8
-#define RSP 19*8
-#define SS 20*8
-
-#define SIZEOF_PTREGS 21*8
-
.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax save_ret=0
.if \save_ret
pushq %rsi /* pt_regs->si */
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 04bddaaba8e2..d8b3ebd2bb85 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -62,7 +62,7 @@ SYM_CODE_START_NOALIGN(startup_64)
*/

/* Set up the stack for verify_cpu(), similar to initial_stack below */
- leaq (__end_init_task - SIZEOF_PTREGS)(%rip), %rsp
+ leaq (__end_init_task - FRAME_SIZE)(%rip), %rsp

leaq _text(%rip), %rdi
pushq %rsi
@@ -343,10 +343,10 @@ SYM_DATA(initial_vc_handler, .quad handle_vc_boot_ghcb)
#endif

/*
- * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder
+ * The FRAME_SIZE gap is a convention which helps the in-kernel unwinder
* reliably detect the end of the stack.
*/
-SYM_DATA(initial_stack, .quad init_thread_union + THREAD_SIZE - SIZEOF_PTREGS)
+SYM_DATA(initial_stack, .quad init_thread_union + THREAD_SIZE - FRAME_SIZE)
__FINITDATA

__INIT
--
2.31.1