From 1e70c680375aa33cca97bff0bca68c0f82f5023c Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Mon, 30 Jan 2023 16:53:54 +0300 Subject: [PATCH] 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: c30c4b2555ba ("x86/tdx: Refactor __tdx_hypercall() to allow pass down more arguments") Reported-by: kernel test robot Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen 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 --- 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 index 5da06d1a9ba3..2bd436a4790d 100644 --- 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 -- 2.20.1