[5.10,23/47] riscv: Use $(LD) instead of $(CC) to link vDSO

Message ID	20210520092054.292173621@linuxfoundation.org
State	New
Headers	show Return-Path: <stable-owner@kernel.org> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>, Fangrui Song <maskray@google.com>, Palmer Dabbelt <palmerdabbelt@google.com>, Sasha Levin <sashal@kernel.org> Subject: [PATCH 5.10 23/47] riscv: Use $(LD) instead of $(CC) to link vDSO Date: Thu, 20 May 2021 11:22:21 +0200 Message-Id: <20210520092054.292173621@linuxfoundation.org> In-Reply-To: <20210520092053.559923764@linuxfoundation.org> References: <20210520092053.559923764@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	None \| expand [5.10,02/47] drm/i915/display: fix compiler warning about array overrun [5.10,03/47] airo: work around stack usage warning [5.10,04/47] kgdb: fix gcc-11 warning on indentation [5.10,05/47] usb: sl811-hcd: improve misleading indentation [5.10,06/47] cxgb4: Fix the -Wmisleading-indentation warning [5.10,07/47] isdn: capi: fix mismatched prototypes [5.10,08/47] virtio_net: Do not pull payload in skb->head [5.10,09/47] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6 [5.10,10/47] PCI: thunder: Fix compile testing [5.10,11/47] dmaengine: dw-edma: Fix crash on loading/unloading driver [5.10,12/47] ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend() [5.10,13/47] ACPI / hotplug / PCI: Fix reference count leak in enable_slot() [5.10,14/47] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert() [5.10,15/47] Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices [5.10,16/47] Input: silead - add workaround for x86 BIOS-es which bring the chip up in a stuck state [5.10,17/47] NFS: NFS_INO_REVAL_PAGECACHE should mark the change attribute invalid [5.10,18/47] um: Mark all kernel symbols as local [5.10,19/47] um: Disable CONFIG_GCOV with MODULES [5.10,20/47] PCI: tegra: Add Tegra194 MCFG quirks for ECAM errata [5.10,21/47] ARM: 9075/1: kernel: Fix interrupted SMC calls [5.10,22/47] platform/chrome: cros_ec_typec: Add DP mode check [5.10,23/47] riscv: Use $(LD) instead of $(CC) to link vDSO [5.10,24/47] scripts/recordmcount.pl: Fix RISC-V regex for clang [5.10,25/47] riscv: Workaround mcount name prior to clang-13 [5.10,26/47] scsi: lpfc: Fix illegal memory access on Abort IOCBs [5.10,27/47] ceph: fix fscache invalidation [5.10,28/47] ceph: dont clobber i_snap_caps on non-I_NEW inode [5.10,29/47] ceph: dont allow access to MDS-private inodes [5.10,30/47] scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found [5.10,31/47] amdgpu/pm: Prevent force of DCEFCLK on NAVI10 and SIENNA_CICHLID [5.10,32/47] bridge: Fix possible races between assigning rx_handler_data and setting IFF_BRIDGE_... [5.10,33/47] net: hsr: check skb can contain struct hsr_ethhdr in fill_frame_info [5.10,34/47] nvmet: remove unsupported command noise [5.10,35/47] drm/amd/display: Fix two cursor duplication when using overlay [5.10,36/47] gpiolib: acpi: Add quirk to ignore EC wakeups on Dell Venue 10 Pro 5055 [5.10,37/47] net:CXGB4: fix leak if sk_buff is not used [5.10,38/47] ALSA: hda: generic: change the DAC ctl name for LO+SPK or LO+HP [5.10,39/47] block: reexpand iov_iter after read/write [5.10,40/47] lib: stackdepot: turn depot_lock spinlock to raw_spinlock [5.10,41/47] net: stmmac: Do not enable RX FIFO overflow interrupts [5.10,42/47] ip6_gre: proper dev_{hold\|put} in ndo_[un]init methods [5.10,43/47] sit: proper dev_{hold\|put} in ndo_[un]init methods [5.10,44/47] ip6_tunnel: sit: proper dev_{hold\|put} in ndo_[un]init methods [5.10,45/47] ipv6: remove extra dev_hold() for fallback tunnels [5.10,46/47] tweewide: Fix most Shebang lines [5.10,47/47] scripts: switch explicitly to Python 3

Message ID

20210520092054.292173621@linuxfoundation.org

State

New

Headers

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
	Fangrui Song <maskray@google.com>,
	Palmer Dabbelt <palmerdabbelt@google.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 23/47] riscv: Use $(LD) instead of $(CC) to link vDSO
Date: Thu, 20 May 2021 11:22:21 +0200
Message-Id: <20210520092054.292173621@linuxfoundation.org>
In-Reply-To: <20210520092053.559923764@linuxfoundation.org>
References: <20210520092053.559923764@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

None | expand

Commit Message

Greg KH May 20, 2021, 9:22 a.m. UTC

From: Nathan Chancellor <nathan@kernel.org>

[ Upstream commit 7f3d349065d0c643f7f7013fbf9bc9f2c90b675f ]

Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When linking with clang, there are a couple of warnings about flags that
will not be used during the link:

clang-12: warning: argument unused during compilation: '-no-pie' [-Wunused-command-line-argument]
clang-12: warning: argument unused during compilation: '-pg' [-Wunused-command-line-argument]

'-no-pie' was added in commit 85602bea297f ("RISC-V: build vdso-dummy.o
with -no-pie") to override '-pie' getting added to the ld command from
distribution versions of GCC that enable PIE by default. It is
technically no longer needed after commit c2c81bb2f691 ("RISC-V: Fix the
VDSO symbol generaton for binutils-2.35+"), which removed vdso-dummy.o
in favor of generating vdso-syms.S from vdso.so with $(NM) but this also
resolves the issue in case it ever comes back due to having full control
over the $(LD) command. '-pg' is for function tracing, it is not used
during linking as clang states.

These flags could be removed/filtered to fix the warnings but it is
easier to just match the rest of the kernel and use $(LD) directly for
linking. See commits

  fe00e50b2db8 ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO")
  691efbedc60d ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO")
  2ff906994b6c ("MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO")
  2b2a25845d53 ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")

for more information.

The flags are converted to linker flags and '--eh-frame-hdr' is added to
match what is added by GCC implicitly, which can be seen by adding '-v'
to GCC's invocation.

Additionally, since this area is being modified, use the $(OBJCOPY)
variable instead of an open coded $(CROSS_COMPILE)objcopy so that the
user's choice of objcopy binary is respected.

Link: https://github.com/ClangBuiltLinux/linux/issues/803
Link: https://github.com/ClangBuiltLinux/linux/issues/970
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/kernel/vdso/Makefile | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 71a315e73cbe..ca2b40dfd24b 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -41,11 +41,10 @@  KASAN_SANITIZE := n
 $(obj)/vdso.o: $(obj)/vdso.so
 
 # link rule for the .so file, .lds has to be first
-SYSCFLAGS_vdso.so.dbg = $(c_flags)
 $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
 	$(call if_changed,vdsold)
-SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
-	-Wl,--build-id=sha1 -Wl,--hash-style=both
+LDFLAGS_vdso.so.dbg = -shared -s -soname=linux-vdso.so.1 \
+	--build-id=sha1 --hash-style=both --eh-frame-hdr
 
 # We also create a special relocatable object that should mirror the symbol
 # table and layout of the linked DSO. With ld --just-symbols we can then
@@ -60,13 +59,10 @@  $(obj)/%.so: $(obj)/%.so.dbg FORCE
 
 # actual build commands
 # The DSO images are built using a special linker script
-# Add -lgcc so rv32 gets static muldi3 and lshrdi3 definitions.
 # Make sure only to export the intended __vdso_xxx symbol offsets.
 quiet_cmd_vdsold = VDSOLD  $@
-      cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \
-                           -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \
-                   $(CROSS_COMPILE)objcopy \
-                           $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
+      cmd_vdsold = $(LD) $(ld_flags) -T $(filter-out FORCE,$^) -o $@.tmp && \
+                   $(OBJCOPY) $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
                    rm $@.tmp
 
 # Extracts symbol offsets from the VDSO, converting them into an assembly file

[5.10,23/47] riscv: Use $(LD) instead of $(CC) to link vDSO

Commit Message

Patch