From: "tip-bot2 for Arvind Sankar" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
Borislav Petkov <bp@suse.de>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: x86/boot] x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len
Date: Wed, 12 Feb 2020 12:04:37 -0000 [thread overview]
Message-ID: <158150907715.411.11504187337643136234.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200211173333.1722739-1-nivedita@alum.mit.edu>
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@alum.mit.edu>
AuthorDate: Tue, 11 Feb 2020 12:33:33 -05:00
Committer: Borislav Petkov <bp@suse.de>
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@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200211173333.1722739-1-nivedita@alum.mit.edu
---
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
next prev parent reply other threads:[~2020-02-12 12:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-07 19:44 [PATCH 1/3] x86/boot/compressed/32: Simplify calculation of output address Arvind Sankar
2020-01-07 19:44 ` [PATCH 2/3] x86/boot/compressed/64: Use leal to initialize boot stack pointer Arvind Sankar
2020-02-12 12:04 ` [tip: x86/boot] x86/boot/compressed/64: Use LEA " tip-bot2 for Arvind Sankar
2020-01-07 19:44 ` [PATCH 3/3] x86/boot/compressed/64: Use 32-bit move for z_output_len Arvind Sankar
2020-02-11 16:17 ` Borislav Petkov
2020-02-11 17:33 ` [PATCH v2] x86/boot: Use 32-bit (zero-extended) " Arvind Sankar
2020-02-11 18:15 ` Borislav Petkov
2020-02-11 19:27 ` Arvind Sankar
2020-02-12 9:47 ` Borislav Petkov
2020-02-12 12:04 ` tip-bot2 for Arvind Sankar [this message]
2020-01-23 11:04 ` [tip: x86/asm] x86/boot: Simplify calculation of output address tip-bot2 for Arvind Sankar
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