From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Scott Wood <oss@buserror.net>, Meelis Roos <mroos@linux.ee>,
Balbir Singh <bsingharora@gmail.com>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2] powerpc: fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX
Date: Tue, 21 Nov 2017 15:28:20 +0100 (CET) [thread overview]
Message-ID: <20171121142820.C744F6BB8F@po15668-vm-win7.idsi0.si.c-s.fr> (raw)
On powerpc32, patch_instruction() is called by apply_feature_fixups()
which is called from early_init()
There is the following note in front of early_init():
* Note that the kernel may be running at an address which is different
* from the address that it was linked at, so we must use RELOC/PTRRELOC
* to access static data (including strings). -- paulus
Therefore, slab_is_available() cannot be called yet, and
text_poke_area must be addressed with PTRRELOC()
Fixes: 37bc3e5fd764f ("powerpc/lib/code-patching: Use alternate map
for patch_instruction()")
Reported-by: Meelis Roos <mroos@linux.ee>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v2: Added missing asm/setup.h
arch/powerpc/lib/code-patching.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index c9de03e0c1f1..d469224c4ada 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -21,6 +21,7 @@
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <asm/code-patching.h>
+#include <asm/setup.h>
static int __patch_instruction(unsigned int *addr, unsigned int instr)
{
@@ -146,11 +147,8 @@ int patch_instruction(unsigned int *addr, unsigned int instr)
* During early early boot patch_instruction is called
* when text_poke_area is not ready, but we still need
* to allow patching. We just do the plain old patching
- * We use slab_is_available and per cpu read * via this_cpu_read
- * of text_poke_area. Per-CPU areas might not be up early
- * this can create problems with just using this_cpu_read()
*/
- if (!slab_is_available() || !this_cpu_read(text_poke_area))
+ if (!this_cpu_read(*PTRRELOC(&text_poke_area)))
return __patch_instruction(addr, instr);
local_irq_save(flags);
--
2.13.3
next reply other threads:[~2017-11-21 14:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-21 14:28 Christophe Leroy [this message]
2017-11-21 17:28 ` [PATCH v2] powerpc: fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX Meelis Roos
2017-11-21 22:22 ` Benjamin Herrenschmidt
2017-11-21 23:07 ` Balbir Singh
2017-11-22 7:16 ` Christophe LEROY
2017-11-22 11:48 ` Michael Ellerman
2017-11-23 7:49 ` Christophe LEROY
2017-11-23 12:04 ` Michael Ellerman
2017-11-25 23:57 ` Balbir Singh
2017-11-22 11:55 ` Michael Ellerman
2017-11-24 9:46 ` [v2] " Michael Ellerman
-- strict thread matches above, loose matches on Subject: below --
2017-11-21 14:26 [PATCH v2] " Christophe Leroy
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