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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Nathan Chancellor <natechancellor@gmail.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Stefan Agner <stefan@agner.ch>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Sasha Levin <sashal@kernel.org>,
	clang-built-linux@googlegroups.com
Subject: [PATCH AUTOSEL 5.2 30/42] ARM: 8905/1: Emit __gnu_mcount_nc when using Clang 10.0.0 or newer
Date: Sun, 29 Sep 2019 13:32:29 -0400	[thread overview]
Message-ID: <20190929173244.8918-30-sashal@kernel.org> (raw)
In-Reply-To: <20190929173244.8918-1-sashal@kernel.org>

From: Nathan Chancellor <natechancellor@gmail.com>

[ Upstream commit b0fe66cf095016e0b238374c10ae366e1f087d11 ]

Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build
with clang:

arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable':
softirq.c:(.text+0x504): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip':
softirq.c:(.text+0x58c): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq':
softirq.c:(.text+0x6c8): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter':
softirq.c:(.text+0x75c): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit':
softirq.c:(.text+0x840): undefined reference to `mcount'
arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow

clang can emit a working mcount symbol, __gnu_mcount_nc, when
'-meabi gnu' is passed to it. Until r369147 in LLVM, this was
broken and caused the kernel not to boot with '-pg' because the
calling convention was not correct. Always build with '-meabi gnu'
when using clang but ensure that '-pg' (which is added with
CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER)
cannot be added with it unless this is fixed (which means using
clang 10.0.0 and newer).

Link: https://github.com/ClangBuiltLinux/linux/issues/35
Link: https://bugs.llvm.org/show_bug.cgi?id=33845
Link: https://github.com/llvm/llvm-project/commit/16fa8b09702378bacfa3d07081afe6b353b99e60

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/Kconfig  | 2 +-
 arch/arm/Makefile | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3539be8700558..6029d324911cf 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -75,7 +75,7 @@ config ARM
 	select HAVE_EXIT_THREAD
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG
-	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
+	select HAVE_FUNCTION_TRACER if !XIP_KERNEL && (CC_IS_GCC || CLANG_VERSION >= 100000)
 	select HAVE_GCC_PLUGINS
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)
 	select HAVE_IDE if PCI || ISA || PCMCIA
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index f863c6935d0e5..c0b2783583016 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -112,6 +112,10 @@ ifeq ($(CONFIG_ARM_UNWIND),y)
 CFLAGS_ABI	+=-funwind-tables
 endif
 
+ifeq ($(CONFIG_CC_IS_CLANG),y)
+CFLAGS_ABI	+= -meabi gnu
+endif
+
 # Accept old syntax despite ".syntax unified"
 AFLAGS_NOWARN	:=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W)
 
-- 
2.20.1


  parent reply	other threads:[~2019-09-29 17:33 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-29 17:32 [PATCH AUTOSEL 5.2 01/42] MIPS: Ingenic: Disable broken BTB lookup optimization Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 02/42] clk: jz4740: Add TCU clock Sasha Levin
2019-09-29 17:32   ` Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 03/42] MIPS: Don't use bc_false uninitialized in __mm_isBranchInstr Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 04/42] MIPS: tlbex: Explicitly cast _PAGE_NO_EXEC to a boolean Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 05/42] i2c-cht-wc: Fix lockdep warning Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 06/42] mfd: intel-lpss: Remove D3cold delay Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 07/42] PCI: tegra: Fix OF node reference leak Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 08/42] HID: wacom: Fix several minor compiler warnings Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 09/42] mips/atomic: Fix loongson_llsc_mb() wreckage Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 10/42] PCI: pci-hyperv: Fix build errors on non-SYSFS config Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 11/42] PCI: layerscape: Add the bar_fixed_64bit property to the endpoint driver Sasha Levin
2019-09-29 17:32   ` Sasha Levin
2019-09-29 17:32   ` Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 12/42] livepatch: Nullify obj->mod in klp_module_coming()'s error path Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 13/42] mips/atomic: Fix smp_mb__{before,after}_atomic() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 14/42] ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 15/42] soundwire: intel: fix channel number reported by hardware Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 16/42] ARM: 8875/1: Kconfig: default to AEABI w/ Clang Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 17/42] MIPS: lantiq: update the clock alias' for the mainline PCIe PHY driver Sasha Levin
2019-09-29 17:39   ` Hauke Mehrtens
2019-10-05 23:00     ` Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 18/42] firmware: bcm47xx_nvram: Correct size_t printf format Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 19/42] rtc: snvs: fix possible race condition Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 20/42] rtc: pcf85363/pcf85263: fix regmap error in set_time Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 21/42] selinux: fix residual uses of current_security() for the SELinux blob Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 22/42] PCI: Add pci_info_ratelimited() to ratelimit PCI separately Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 23/42] HID: apple: Fix stuck function keys when using FN Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 24/42] PCI: rockchip: Propagate errors for optional regulators Sasha Levin
2019-09-29 17:32   ` Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 25/42] PCI: histb: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 26/42] PCI: imx6: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 27/42] PCI: exynos: Propagate errors for optional PHYs Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 28/42] security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 29/42] PCI: Use static const struct, not const static struct Sasha Levin
2019-09-29 17:32 ` Sasha Levin [this message]
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 31/42] ARM: 8903/1: ensure that usable memory in bank 0 starts from a PMD-aligned address Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 32/42] fat: work around race with userspace's read via blockdev while mounting Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 33/42] pktcdvd: remove warning on attempting to register non-passthrough dev Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 34/42] hypfs: Fix error number left in struct pointer member Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 35/42] crypto: hisilicon - Fix double free in sec_free_hw_sgl() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 36/42] kbuild: clean compressed initramfs image Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 37/42] ocfs2: wait for recovering done after direct unlock request Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 38/42] kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 39/42] arm64: consider stack randomization for mmap base only when necessary Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 40/42] mips: properly account for stack randomization and stack guard gap Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 41/42] arm: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 42/42] arm: use STACK_TOP when computing mmap base address Sasha Levin

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