On Thu, 2 Sept 2021 at 10:04, Ilias Apalodimas
<ilias.apalodimas@xxxxxxxxxx> wrote:
>
> From: Ard Biesheuvel <ardb@xxxxxxxxxx>
>
> Increase the number of arguments supported by mixed mode calls, so that
> we will be able to call into the TCG2 protocol to measure the initrd
> and extend the associated PCR. This involves the TCG2 protocol's
> hash_log_extend_event() method, which takes five arguments, three of
> which are u64 and need to be split, producing a total of 8 outgoing
> arguments.
>
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Does this still apply cleanly? There was a last minute fix that went
into v5.14 that looked like it would conflict with this.
> ---
> arch/x86/boot/compressed/efi_thunk_64.S | 17 ++++++++++++-----
> arch/x86/include/asm/efi.h | 10 ++++++----
> arch/x86/platform/efi/efi_thunk_64.S | 14 ++++++++++++--
> 3 files changed, 30 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S
> index 95a223b3e56a..fec6c48d6b30 100644
> --- a/arch/x86/boot/compressed/efi_thunk_64.S
> +++ b/arch/x86/boot/compressed/efi_thunk_64.S
> @@ -27,8 +27,6 @@ SYM_FUNC_START(__efi64_thunk)
> push %rbp
> push %rbx
>
> - leaq 1f(%rip), %rbp
> -
> movl %ds, %eax
> push %rax
> movl %es, %eax
> @@ -36,19 +34,28 @@ SYM_FUNC_START(__efi64_thunk)
> movl %ss, %eax
> push %rax
>
> + movq 0x30(%rsp), %rbp
> + movq 0x38(%rsp), %rbx
> + movq 0x40(%rsp), %rax
> +
> /*
> * Convert x86-64 ABI params to i386 ABI
> */
> - subq $32, %rsp
> + subq $48, %rsp
> movl %esi, 0x0(%rsp)
> movl %edx, 0x4(%rsp)
> movl %ecx, 0x8(%rsp)
> movl %r8d, 0xc(%rsp)
> movl %r9d, 0x10(%rsp)
> + movl %ebp, 0x14(%rsp)
> + movl %ebx, 0x18(%rsp)
> + movl %eax, 0x1c(%rsp)
>
> - leaq 0x14(%rsp), %rbx
> + leaq 0x20(%rsp), %rbx
> sgdt (%rbx)
>
> + leaq 1f(%rip), %rbp
> +
> /*
> * Switch to gdt with 32-bit segments. This is the firmware GDT
> * that was installed when the kernel started executing. This
> @@ -67,7 +74,7 @@ SYM_FUNC_START(__efi64_thunk)
> pushq %rax
> lretq
>
> -1: addq $32, %rsp
> +1: addq $48, %rsp
> movq %rdi, %rax
>
> pop %rbx
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 85f156f8ef81..a323dbac9182 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -46,13 +46,14 @@ extern unsigned long efi_mixed_mode_stack_pa;
>
> #define __efi_nargs(...) __efi_nargs_(__VA_ARGS__)
> #define __efi_nargs_(...) __efi_nargs__(0, ##__VA_ARGS__, \
> + __efi_arg_sentinel(9), __efi_arg_sentinel(8), \
> __efi_arg_sentinel(7), __efi_arg_sentinel(6), \
> __efi_arg_sentinel(5), __efi_arg_sentinel(4), \
> __efi_arg_sentinel(3), __efi_arg_sentinel(2), \
> __efi_arg_sentinel(1), __efi_arg_sentinel(0))
> -#define __efi_nargs__(_0, _1, _2, _3, _4, _5, _6, _7, n, ...) \
> +#define __efi_nargs__(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, ...) \
> __take_second_arg(n, \
> - ({ BUILD_BUG_ON_MSG(1, "__efi_nargs limit exceeded"); 8; }))
> + ({ BUILD_BUG_ON_MSG(1, "__efi_nargs limit exceeded"); 10; }))
> #define __efi_arg_sentinel(n) , n
>
> /*
> @@ -176,8 +177,9 @@ extern u64 efi_setup;
> extern efi_status_t __efi64_thunk(u32, ...);
>
> #define efi64_thunk(...) ({ \
> - __efi_nargs_check(efi64_thunk, 6, __VA_ARGS__); \
> - __efi64_thunk(__VA_ARGS__); \
> + u64 __pad[3]; /* must have space for 3 args on the stack */ \
> + __efi_nargs_check(efi64_thunk, 9, __VA_ARGS__); \
> + __efi64_thunk(__VA_ARGS__, __pad); \
> })
>
> static inline bool efi_is_mixed(void)
> diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S
> index fd3dd1708eba..5b7c6e09954e 100644
> --- a/arch/x86/platform/efi/efi_thunk_64.S
> +++ b/arch/x86/platform/efi/efi_thunk_64.S
> @@ -36,6 +36,17 @@ SYM_CODE_START(__efi64_thunk)
> movq efi_mixed_mode_stack_pa(%rip), %rsp
> push %rax
>
> + /*
> + * Copy args passed via the stack
> + */
> + subq $0x24, %rsp
> + movq 0x18(%rax), %rbp
> + movq 0x20(%rax), %rbx
> + movq 0x28(%rax), %rax
> + movl %ebp, 0x18(%rsp)
> + movl %ebx, 0x1c(%rsp)
> + movl %eax, 0x20(%rsp)
> +
> /*
> * Calculate the physical address of the kernel text.
> */
> @@ -47,7 +58,6 @@ SYM_CODE_START(__efi64_thunk)
> subq %rax, %rbp
> subq %rax, %rbx
>
> - subq $28, %rsp
> movl %ebx, 0x0(%rsp) /* return address */
> movl %esi, 0x4(%rsp)
> movl %edx, 0x8(%rsp)
> @@ -60,7 +70,7 @@ SYM_CODE_START(__efi64_thunk)
> pushq %rdi /* EFI runtime service address */
> lretq
>
> -1: movq 24(%rsp), %rsp
> +1: movq 0x20(%rsp), %rsp
> pop %rbx
> pop %rbp
> retq
> --
> 2.32.0.rc0
>
