linux/include
Ard Biesheuvel 73cfc53cc3 objtool: Fix C jump table annotations for Clang
A C jump table (such as the one used by the BPF interpreter) is a const
global array of absolute code addresses, and this means that the actual
values in the table may not be known until the kernel is booted (e.g.,
when using KASLR or when the kernel VA space is sized dynamically).

When using PIE codegen, the compiler will default to placing such const
global objects in .data.rel.ro (which is annotated as writable), rather
than .rodata (which is annotated as read-only). As C jump tables are
explicitly emitted into .rodata, this used to result in warnings for
LoongArch builds (which uses PIE codegen for the entire kernel) like

  Warning: setting incorrect section attributes for .rodata..c_jump_table

due to the fact that the explicitly specified .rodata section inherited
the read-write annotation that the compiler uses for such objects when
using PIE codegen.

This warning was suppressed by explicitly adding the read-only
annotation to the __attribute__((section(""))) string, by commit

  c5b1184dec ("compiler.h: specify correct attribute for .rodata..c_jump_table")

Unfortunately, this hack does not work on Clang's integrated assembler,
which happily interprets the appended section type and permission
specifiers as part of the section name, which therefore no longer
matches the hard-coded pattern '.rodata..c_jump_table' that objtool
expects, causing it to emit a warning

  kernel/bpf/core.o: warning: objtool: ___bpf_prog_run+0x20: sibling call from callable instruction with modified stack frame

Work around this, by emitting C jump tables into .data.rel.ro instead,
which is treated as .rodata by the linker script for all builds, not
just PIE based ones.

Fixes: c5b1184dec ("compiler.h: specify correct attribute for .rodata..c_jump_table")
Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> # on LoongArch
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250221135704.431269-6-ardb+git@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
History 2025-02-25 09:46:16 -08:00
..
acpi LoongArch changes for v6.14 2025-01-28 08:52:01 -08:00
asm-generic vmlinux.lds: Ensure that const vars with relocations are mapped R/O 2025-02-25 09:46:15 -08:00
clocksource KVM/arm64 updates for 6.14 2025-01-28 09:01:36 -08:00
crypto crypto: skcipher - document skcipher_walk_done() and rename some vars 2025-01-14 11:38:32 +08:00
cxl cxl/events: Update Memory Module Event Record to CXL spec rev 3.1 2025-01-13 09:33:21 -07:00
drm drm/bridge: fix documentation for the hdmi_audio_prepare() callback 2025-01-15 12:32:47 +02:00
dt-bindings Char/Misc/IIO driver updates for 6.14-rc1 2025-01-27 16:51:51 -08:00
hyperv hyperv: Add new Hyper-V headers in include/hyperv 2025-01-10 00:54:20 +00:00
keys keys: drop shadowing dead prototype 2025-01-21 11:25:23 +02:00
kunit linux_kselftest-kunit-6.14-rc1 2025-01-22 12:32:39 -08:00
kvm Merge branch kvm-arm64/pkvm-memshare-declutter into kvmarm-master/next 2025-01-17 11:05:18 +00:00
linux objtool: Fix C jump table annotations for Clang 2025-02-25 09:46:16 -08:00
math-emu powerpc/math-emu: Remove -w build flag and fix warnings 2022-09-05 17:28:25 +10:00
media media: cec: include linux/debugfs.h and linux/seq_file.h where needed 2025-01-07 12:21:38 +01:00
memory memory: renesas-rpc-if: Remove Runtime PM wrappers 2023-01-23 11:48:00 +01:00
misc cxl: fix typo in comment 2022-11-24 23:12:19 +11:00
net ipsec-2025-01-27 2025-01-27 15:15:12 -08:00
pcmcia ARM: pxa/sa1100: move I/O space to PCI_IOBASE 2022-05-07 22:56:17 +02:00
ras mm/memory-failure: remove obsolete MF_MSG_DIFFERENT_COMPOUND 2024-07-12 15:52:22 -07:00
rdma RDMA/core: Support link status events dispatching 2024-12-24 05:22:18 -05:00
rv rv: Reset per-task monitors also for idle tasks 2025-01-23 12:16:04 -05:00
scsi Driver core and debugfs updates 2025-01-28 12:25:12 -08:00
soc soc: driver updates for 6.14 2025-01-24 14:56:59 -08:00
sound sound updates for 6.14-rc1 2025-01-24 07:54:34 -08:00
target scsi: target: iscsi: switch to using the crc32c library 2024-12-01 17:23:02 -08:00
trace f2fs-for-6.14-rc1 2025-01-27 20:58:58 -08:00
uapi This pull request contains updates for UBI and UBIFS: 2025-01-30 18:27:02 -08:00
ufs scsi: Revert "scsi: ufs: core: Probe for EXT_IID support" 2025-01-10 16:38:21 -05:00
vdso vdso: Correct typo in PAGE_SHIFT comment 2025-01-15 11:07:08 +01:00
video - Improved handling of LCD power states and interactions with the fbdev subsystem. 2024-11-22 16:29:57 -08:00
xen xen: Remove dependency between pciback and privcmd 2024-10-18 11:59:04 +02:00