The following commit has been merged into the x86/boot branch of tip: Commit-ID: a86255fe5258714e1f7c1bdfe95f08e4d098d450 Gitweb: https://git.kernel.org/tip/a86255fe5258714e1f7c1bdfe95f08e4d098d450 Author: Arvind Sankar <nivedita@xxxxxxxxxxxx> AuthorDate: Tue, 11 Feb 2020 12:33:33 -05:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Wed, 12 Feb 2020 11:15:31 +01:00 x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len z_output_len is the size of the decompressed payload (i.e. vmlinux + vmlinux.relocs) and is generated as an unsigned 32-bit quantity by mkpiggy.c. The current movq $z_output_len, %r9 instruction generates a sign-extended move to %r9. Using movl $z_output_len, %r9d will instead zero-extend into %r9, which is appropriate for an unsigned 32-bit quantity. This is also what is already done for z_input_len, the size of the compressed payload. [ bp: Also, z_output_len cannot be a 64-bit quantity because it participates in: init_size: .long INIT_SIZE # kernel initialization size through INIT_SIZE which is a 32-bit quantity determined by the .long directive (vs .quad for 64-bit). Furthermore, if it really must be a 64-bit quantity, then the insn must be MOVABS which can accommodate a 64-bit immediate and which the toolchain does not generate automatically. ] Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20200211173333.1722739-1-nivedita@xxxxxxxxxxxx --- arch/x86/boot/compressed/head_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index d1220de..68f31c4 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -482,7 +482,7 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) leaq input_data(%rip), %rdx /* input_data */ movl $z_input_len, %ecx /* input_len */ movq %rbp, %r8 /* output target address */ - movq $z_output_len, %r9 /* decompressed length, end of relocs */ + movl $z_output_len, %r9d /* decompressed length, end of relocs */ call extract_kernel /* returns kernel location in %rax */ popq %rsi
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