From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk
Cc: Ard Biesheuvel <ardb@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
kernel test robot <lkp@intel.com>
Subject: [PATCH] ARM: entry: add .ltorg directive to keep literals in range
Date: Mon, 30 May 2022 13:24:17 +0200 [thread overview]
Message-ID: <20220530112417.2492510-1-ardb@kernel.org> (raw)
LKP reports a build issue on Clang, related to a literal load of
__current issued through the ldr_va macro. This turns out to be due to
the fact that group relocations are disabled when CONFIG_COMPILE_TEST=y,
which means that the ldr_va macro resolves to a pair of LDR
instructions, the first one being a literal load issued too far from its
literal pool.
Due to the introduction of a couple of new uses of this macro in commit
508074607c7b95b2 ("ARM: 9195/1: entry: avoid explicit literal loads"),
the literal pools end up getting rearranged in a way that causes the
literal for __current to go out of range. Let's fix this up by putting a
.ltorg directive in a suitable place in the code.
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Fixes: 508074607c7b95b2 ("ARM: 9195/1: entry: avoid explicit literal loads")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202205290805.1vZLAr36-lkp@intel.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm/kernel/entry-common.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 7aa3ded4af92..6a447ac67d80 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -298,14 +298,15 @@ local_restart:
9001:
sub lr, saved_pc, #4
str lr, [sp, #S_PC]
get_thread_info tsk
b ret_fast_syscall
#endif
ENDPROC(vector_swi)
+ .ltorg
/*
* This is the really slow path. We're going to be doing
* context switches, and waiting for our parent to respond.
*/
__sys_trace:
add r0, sp, #S_OFF
--
2.30.2
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next reply other threads:[~2022-05-30 11:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-30 11:24 Ard Biesheuvel [this message]
2022-05-31 15:29 ` [PATCH] ARM: entry: add .ltorg directive to keep literals in range Nathan Chancellor
2022-06-01 11:35 ` Ard Biesheuvel
2022-06-08 18:42 ` Nick Desaulniers
2022-06-08 20:29 ` Ard Biesheuvel
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