From: Nick Desaulniers <ndesaulniers@google.com>
To: miguel.ojeda.sandonis@gmail.com
Cc: sedat.dilek@gmail.com, will@kernel.org, jpoimboe@redhat.com,
naveen.n.rao@linux.vnet.ibm.com, davem@davemloft.net,
paul.burton@mips.com, clang-built-linux@googlegroups.com,
linux-kernel@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH v3 10/14] x86: prefer __section from compiler_attributes.h
Date: Wed, 28 Aug 2019 15:55:31 -0700 [thread overview]
Message-ID: <20190828225535.49592-11-ndesaulniers@google.com> (raw)
In-Reply-To: <20190828225535.49592-1-ndesaulniers@google.com>
GCC unescapes escaped string section names while Clang does not. Because
__section uses the `#` stringification operator for the section name, it
doesn't need to be escaped.
Instead, we should:
1. Prefer __section(.section_name_no_quotes).
2. Only use __attribute__((__section__(".section"))) when creating the
section name via C preprocessor (see the definition of __define_initcall
in arch/um/include/shared/init.h).
This antipattern was found with:
$ grep -e __section\(\" -e __section__\(\" -r
See the discussions in:
Link: https://bugs.llvm.org/show_bug.cgi?id=42950
Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2
Link: https://github.com/ClangBuiltLinux/linux/issues/619
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
arch/x86/include/asm/cache.h | 2 +-
arch/x86/include/asm/intel-mid.h | 2 +-
arch/x86/include/asm/iommu_table.h | 5 ++---
arch/x86/include/asm/irqflags.h | 2 +-
arch/x86/include/asm/mem_encrypt.h | 2 +-
arch/x86/kernel/cpu/cpu.h | 3 +--
6 files changed, 7 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/cache.h b/arch/x86/include/asm/cache.h
index abe08690a887..bb9f4bf4ec02 100644
--- a/arch/x86/include/asm/cache.h
+++ b/arch/x86/include/asm/cache.h
@@ -8,7 +8,7 @@
#define L1_CACHE_SHIFT (CONFIG_X86_L1_CACHE_SHIFT)
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
-#define __read_mostly __attribute__((__section__(".data..read_mostly")))
+#define __read_mostly __section(.data..read_mostly)
#define INTERNODE_CACHE_SHIFT CONFIG_X86_INTERNODE_CACHE_SHIFT
#define INTERNODE_CACHE_BYTES (1 << INTERNODE_CACHE_SHIFT)
diff --git a/arch/x86/include/asm/intel-mid.h b/arch/x86/include/asm/intel-mid.h
index 8e5af119dc2d..f51f04aefe1b 100644
--- a/arch/x86/include/asm/intel-mid.h
+++ b/arch/x86/include/asm/intel-mid.h
@@ -43,7 +43,7 @@ struct devs_id {
#define sfi_device(i) \
static const struct devs_id *const __intel_mid_sfi_##i##_dev __used \
- __attribute__((__section__(".x86_intel_mid_dev.init"))) = &i
+ __section(.x86_intel_mid_dev.init) = &i
/**
* struct mid_sd_board_info - template for SD device creation
diff --git a/arch/x86/include/asm/iommu_table.h b/arch/x86/include/asm/iommu_table.h
index 1fb3fd1a83c2..7d190710eb92 100644
--- a/arch/x86/include/asm/iommu_table.h
+++ b/arch/x86/include/asm/iommu_table.h
@@ -50,9 +50,8 @@ struct iommu_table_entry {
#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
static const struct iommu_table_entry \
- __iommu_entry_##_detect __used \
- __attribute__ ((unused, __section__(".iommu_table"), \
- aligned((sizeof(void *))))) \
+ __iommu_entry_##_detect __used __section(.iommu_table) \
+ __aligned((sizeof(void *))) \
= {_detect, _depend, _early_init, _late_init, \
_finish ? IOMMU_FINISH_IF_DETECTED : 0}
/*
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 8a0e56e1dcc9..68db90bca813 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -9,7 +9,7 @@
#include <asm/nospec-branch.h>
/* Provide __cpuidle; we can't safely include <linux/cpu.h> */
-#define __cpuidle __attribute__((__section__(".cpuidle.text")))
+#define __cpuidle __section(.cpuidle.text)
/*
* Interrupt control:
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 0c196c47d621..db2cd3709148 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -50,7 +50,7 @@ void __init mem_encrypt_free_decrypted_mem(void);
bool sme_active(void);
bool sev_active(void);
-#define __bss_decrypted __attribute__((__section__(".bss..decrypted")))
+#define __bss_decrypted __section(.bss..decrypted)
#else /* !CONFIG_AMD_MEM_ENCRYPT */
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index c0e2407abdd6..7ff9dc41a603 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -38,8 +38,7 @@ struct _tlb_table {
#define cpu_dev_register(cpu_devX) \
static const struct cpu_dev *const __cpu_dev_##cpu_devX __used \
- __attribute__((__section__(".x86_cpu_dev.init"))) = \
- &cpu_devX;
+ __section(.x86_cpu_dev.init) = &cpu_devX;
extern const struct cpu_dev *const __x86_cpu_dev_start[],
*const __x86_cpu_dev_end[];
--
2.23.0.187.g17f5b7556c-goog
next prev parent reply other threads:[~2019-08-28 22:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 22:55 [PATCH v3 00/14] treewide: prefer __section from compiler_attributes.h Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 01/14] s390/boot: fix section name escaping Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 02/14] include/linux/compiler.h: prefer __section from compiler_attributes.h Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 03/14] parisc: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 04/14] um: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 05/14] ia64: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 06/14] arm: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 07/14] mips: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 08/14] sparc: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 09/14] powerpc: prefer __section and __printf " Nick Desaulniers
2019-08-28 22:55 ` Nick Desaulniers [this message]
2019-08-29 14:14 ` [PATCH v3 10/14] x86: prefer __section " Miguel Ojeda
2019-08-29 14:22 ` Miguel Ojeda
2019-08-28 22:55 ` [PATCH v3 11/14] include/asm-generic: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 12/14] include/linux: " Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 13/14] include/linux/compiler.h: remove unused KENTRY macro Nick Desaulniers
2019-08-28 22:55 ` [PATCH v3 14/14] compiler_attributes.h: add note about __section Nick Desaulniers
2019-08-29 20:24 ` [PATCH v3 00/14] treewide: prefer __section from compiler_attributes.h Miguel Ojeda
2019-08-29 20:37 ` Sedat Dilek
2019-08-29 20:47 ` Nick Desaulniers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190828225535.49592-11-ndesaulniers@google.com \
--to=ndesaulniers@google.com \
--cc=clang-built-linux@googlegroups.com \
--cc=davem@davemloft.net \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=miguel.ojeda.sandonis@gmail.com \
--cc=naveen.n.rao@linux.vnet.ibm.com \
--cc=paul.burton@mips.com \
--cc=sedat.dilek@gmail.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).