From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Mon, 30 Jan 2023 16:53:54 +0300
Patch-mainline: v6.3-rc1
Subject: x86/tdx: Do not corrupt frame-pointer in __tdx_hypercall()
Git-commit: 1e70c680375aa33cca97bff0bca68c0f82f5023c
References: bsc#1206453
If compiled with CONFIG_FRAME_POINTER=y, objtool is not happy that
__tdx_hypercall() messes up RBP:
objtool: __tdx_hypercall+0x7f: return with modified stack frame
Rework the function to store TDX_HCALL_ flags on stack instead of RBP.
[ dhansen: minor changelog tweaks ]
Fixes: c30c4b2555ba ("x86/tdx: Refactor __tdx_hypercall() to allow pass down more arguments")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/202301290255.buUBs99R-lkp@intel.com
Link: https://lore.kernel.org/all/20230130135354.27674-1-kirill.shutemov%40linux.intel.com
Acked-by: Olaf Hering <ohering@suse.de>
---
arch/x86/coco/tdx/tdcall.S | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S
--- a/arch/x86/coco/tdx/tdcall.S
+++ b/arch/x86/coco/tdx/tdcall.S
@@ -131,11 +131,10 @@ SYM_FUNC_START(__tdx_hypercall)
push %r13
push %r12
push %rbx
- push %rbp
/* Free RDI and RSI to be used as TDVMCALL arguments */
movq %rdi, %rax
- movq %rsi, %rbp
+ push %rsi
/* Copy hypercall registers from arg struct: */
movq TDX_HYPERCALL_r8(%rax), %r8
@@ -168,7 +167,7 @@ SYM_FUNC_START(__tdx_hypercall)
* HLT operation indefinitely. Since this is the not the desired
* result, conditionally call STI before TDCALL.
*/
- testq $TDX_HCALL_ISSUE_STI, %rbp
+ testq $TDX_HCALL_ISSUE_STI, 8(%rsp)
jz .Lskip_sti
sti
.Lskip_sti:
@@ -188,7 +187,7 @@ SYM_FUNC_START(__tdx_hypercall)
pop %rax
/* Copy hypercall result registers to arg struct if needed */
- testq $TDX_HCALL_HAS_OUTPUT, %rbp
+ testq $TDX_HCALL_HAS_OUTPUT, (%rsp)
jz .Lout
movq %r8, TDX_HYPERCALL_r8(%rax)
@@ -218,11 +217,12 @@ SYM_FUNC_START(__tdx_hypercall)
xor %r10d, %r10d
xor %r11d, %r11d
xor %rdi, %rdi
- xor %rsi, %rsi
xor %rdx, %rdx
+ /* Remove TDX_HCALL_* flags from the stack */
+ pop %rsi
+
/* Restore callee-saved GPRs as mandated by the x86_64 ABI */
- pop %rbp
pop %rbx
pop %r12
pop %r13