x86/tdx: Do not corrupt frame-pointer in __tdx_hypercall()

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: c30c4b2555 ("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
This commit is contained in:
Kirill A. Shutemov 2023-01-30 16:53:54 +03:00 committed by Dave Hansen
parent 8de62af018
commit 1e70c68037

View File

@ -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