Instead of storing the return address in a global variable when calling
a 32-bit EFI service from the 64-bit stub, avoid the indirection via
efi_exit32, and take the return address from the stack.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-26-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
* needs to be able to service interrupts.
*
* On the plus side, we don't have to worry about mangling 64-bit
* needs to be able to service interrupts.
*
* On the plus side, we don't have to worry about mangling 64-bit
- * addresses into 32-bits because we're executing with an identify
+ * addresses into 32-bits because we're executing with an identity
* mapped pagetable and haven't transitioned to 64-bit virtual addresses
* yet.
*/
* mapped pagetable and haven't transitioned to 64-bit virtual addresses
* yet.
*/
- leaq efi_exit32(%rip), %rax
movl %eax, 4(%rsp)
leaq efi_gdt64(%rip), %rax
movl %eax, (%rsp)
movl %eax, 4(%rsp)
leaq efi_gdt64(%rip), %rax
movl %eax, (%rsp)
- leaq 1f(%rip), %rbx
- movq %rbx, func_rt_ptr(%rip)
-
/*
* Switch to gdt with 32-bit segments. This is the firmware GDT
* that was installed when the kernel started executing. This
/*
* Switch to gdt with 32-bit segments. This is the firmware GDT
* that was installed when the kernel started executing. This
ret
SYM_FUNC_END(efi64_thunk)
ret
SYM_FUNC_END(efi64_thunk)
-SYM_FUNC_START_LOCAL(efi_exit32)
- movq func_rt_ptr(%rip), %rax
- push %rax
- mov %rdi, %rax
- ret
-SYM_FUNC_END(efi_exit32)
-
.code32
/*
* EFI service pointer must be in %edi.
.code32
/*
* EFI service pointer must be in %edi.
.quad 0
SYM_DATA_END(save_gdt)
.quad 0
SYM_DATA_END(save_gdt)
-SYM_DATA_LOCAL(func_rt_ptr, .quad 0)
-
SYM_DATA_START(efi_gdt64)
.word efi_gdt64_end - efi_gdt64
.long 0 /* Filled out by user */
SYM_DATA_START(efi_gdt64)
.word efi_gdt64_end - efi_gdt64
.long 0 /* Filled out by user */