[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.16] x86: fix early boot output
commit 6ede73cab9ec9cf1ad0be0224279b645b84d1a9a Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Thu Aug 3 16:32:28 2023 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Thu Aug 3 16:32:28 2023 +0200 x86: fix early boot output Loading the VGA base address involves sym_esi(), i.e. %esi still needs to hold the relocation base address. Therefore the address of the message to output cannot be "passed" in %esi. Put the message offset in %ecx instead, adding it into %esi _after_ its last use as base address. Fixes: b28044226e1c ("x86: make Xen early boot code relocatable") Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> master commit: b1c16800e52743d9afd9af62c810f03af16dd942 master date: 2023-07-19 10:22:56 +0200 --- xen/arch/x86/boot/head.S | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S index dd1bea0d10..e1b05a2557 100644 --- a/xen/arch/x86/boot/head.S +++ b/xen/arch/x86/boot/head.S @@ -141,21 +141,21 @@ efi_platform: .section .init.text, "ax", @progbits bad_cpu: - add $sym_offs(.Lbad_cpu_msg),%esi # Error message + mov $sym_offs(.Lbad_cpu_msg), %ecx jmp .Lget_vtb not_multiboot: - add $sym_offs(.Lbad_ldr_msg),%esi # Error message + mov $sym_offs(.Lbad_ldr_msg), %ecx jmp .Lget_vtb .Lmb2_no_st: /* * Here we are on EFI platform. vga_text_buffer was zapped earlier * because there is pretty good chance that VGA is unavailable. */ - add $sym_offs(.Lbad_ldr_nst),%esi # Error message + mov $sym_offs(.Lbad_ldr_nst), %ecx jmp .Lget_vtb .Lmb2_no_ih: /* Ditto. */ - add $sym_offs(.Lbad_ldr_nih),%esi # Error message + mov $sym_offs(.Lbad_ldr_nih), %ecx jmp .Lget_vtb .Lmb2_no_bs: /* @@ -163,7 +163,7 @@ not_multiboot: * via start label. Then reliable vga_text_buffer zap is impossible * in Multiboot2 scanning loop and we have to zero %edi below. */ - add $sym_offs(.Lbad_ldr_nbs),%esi # Error message + mov $sym_offs(.Lbad_ldr_nbs), %ecx xor %edi,%edi # No VGA text buffer jmp .Lprint_err .Lmb2_efi_ia_32: @@ -171,12 +171,15 @@ not_multiboot: * Here we are on EFI IA-32 platform. Then reliable vga_text_buffer zap is * impossible in Multiboot2 scanning loop and we have to zero %edi below. */ - add $sym_offs(.Lbad_efi_msg),%esi # Error message + mov $sym_offs(.Lbad_efi_msg), %ecx xor %edi,%edi # No VGA text buffer jmp .Lprint_err .Lget_vtb: mov sym_esi(vga_text_buffer),%edi .Lprint_err: + add %ecx, %esi # Add string offset to relocation base. + # NOTE: No further use of sym_esi() till the end of the "function"! +1: lodsb test %al,%al # Terminate on '\0' sentinel je .Lhalt @@ -189,11 +192,11 @@ not_multiboot: mov %bl,%al out %al,%dx # Send a character over the serial line test %edi,%edi # Is the VGA text buffer available? - jz .Lprint_err + jz 1b stosb # Write a character to the VGA text buffer mov $7,%al stosb # Write an attribute to the VGA text buffer - jmp .Lprint_err + jmp 1b .Lhalt: hlt jmp .Lhalt -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.16
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