From: Jason Yan <yanaijie@huawei.com>
To: <mpe@ellerman.id.au>, <linuxppc-dev@lists.ozlabs.org>,
<diana.craciun@nxp.com>, <christophe.leroy@c-s.fr>,
<benh@kernel.crashing.org>, <paulus@samba.org>,
<npiggin@gmail.com>, <keescook@chromium.org>,
<kernel-hardening@lists.openwall.com>, <oss@buserror.net>
Cc: <linux-kernel@vger.kernel.org>, <zhaohongjiang@huawei.com>,
Jason Yan <yanaijie@huawei.com>
Subject: [PATCH v2 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass
Date: Wed, 5 Feb 2020 10:55:25 +0800 [thread overview]
Message-ID: <20200205025527.28640-5-yanaijie@huawei.com> (raw)
In-Reply-To: <20200205025527.28640-1-yanaijie@huawei.com>
The BSS section has already cleared out in the first pass. No need to
clear it again. This can save some time when booting with KASLR
enabled.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
arch/powerpc/kernel/head_64.S | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index b4ececc4323d..9ae7fd8bbf7c 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -914,6 +914,13 @@ start_here_multiplatform:
bl relative_toc
tovirt(r2,r2)
+ /* Do not clear the BSS for the second pass if randomized */
+ LOAD_REG_ADDR(r3, kernstart_virt_addr)
+ lwz r3,0(r3)
+ LOAD_REG_IMMEDIATE(r4, KERNELBASE)
+ cmpw r3,r4
+ bne 4f
+
/* Clear out the BSS. It may have been done in prom_init,
* already but that's irrelevant since prom_init will soon
* be detached from the kernel completely. Besides, we need
--
2.17.2
next prev parent reply other threads:[~2020-02-05 2:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 2:55 [PATCH v2 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
2020-02-05 2:55 ` [PATCH v2 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
2020-02-05 2:55 ` [PATCH v2 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper Jason Yan
2020-02-05 2:55 ` [PATCH v2 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Jason Yan
2020-02-05 5:13 ` kbuild test robot
2020-02-05 2:55 ` Jason Yan [this message]
2020-02-05 2:55 ` [PATCH v2 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized Jason Yan
2020-02-05 2:55 ` [PATCH v2 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part Jason Yan
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