TencentOS-kernel/arch
John Millikin 4a9a3dfff2 x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)
[ Upstream commit 8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d ]

When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable
contains additional flags needed to build C and assembly sources
for the target platform. Normally this variable is automatically
included in `$(KBUILD_CFLAGS)' via the top-level Makefile.

The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a
plain assignment and therefore drops the Clang flags. This causes
Clang to not recognize x86-specific assembler directives:

  arch/x86/realmode/rm/header.S:36:1: error: unknown directive
  .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header
  ^

Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)',
which is inherited by real-mode make rules, fixes cross-compilation
with Clang for x86 targets.

Relevant flags:

* `--target' sets the target architecture when cross-compiling. This
  flag must be set for both compilation and assembly (`KBUILD_AFLAGS')
  to support architecture-specific assembler directives.

* `-no-integrated-as' tells clang to assemble with GNU Assembler
  instead of its built-in LLVM assembler. This flag is set by default
  unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet
  parse certain GNU extensions.

Signed-off-by: John Millikin <john@john-millikin.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://lkml.kernel.org/r/20210326000435.4785-2-nathan@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-20 16:07:24 +08:00
..
alpha alpha: fix annotation of io{read,write}{16,32}be() 2021-03-16 16:34:34 +08:00
arc arc: kernel: Return -EFAULT if copy_to_user() fails 2021-05-20 16:07:08 +08:00
arm ARM: 9056/1: decompressor: fix BSS size calculation for LLVM ld.lld 2021-05-20 16:07:19 +08:00
arm64 arm64: dts: mt8173: fix property typo of 'phys' in dsi node 2021-05-20 16:07:19 +08:00
c6x Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
csky csky: change a Kconfig symbol name to fix e1000 build error 2021-05-20 16:07:15 +08:00
h8300 h8300: fix PREEMPTION build, TI_PRE_COUNT undefined 2021-04-12 12:52:05 +08:00
hexagon hexagon: define ioremap_uc 2021-03-16 16:27:29 +08:00
ia64 ia64: fix discontig.c section mismatches 2021-05-20 16:07:15 +08:00
m68k m68k: q40: Fix info-leak in rtc_ioctl 2021-03-16 16:36:33 +08:00
microblaze Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
mips mips: Do not include hi and lo in clobber list for R6 2021-05-20 16:07:17 +08:00
nds32 nds32: flush_dcache_page: use page_mapping_file to avoid races with swapoff 2021-05-20 16:06:56 +08:00
nios2 Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
openrisc openrisc: Fix issue with get_user for 64-bit values 2021-03-16 16:39:36 +08:00
parisc parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers 2021-05-20 16:06:56 +08:00
powerpc powerpc: Force inlining of cpu_has_feature() to avoid build failure 2021-05-20 16:06:46 +08:00
riscv riscv: Fix spelling mistake "SPARSEMEM" to "SPARSMEM" 2021-05-20 16:07:11 +08:00
s390 s390/disassembler: increase ebpf disasm buffer size 2021-05-20 16:07:19 +08:00
sh sh: dma: fix kconfig dependency for G2_DMA 2021-04-12 12:51:39 +08:00
sparc sparc64: Fix opcode filtering in handling of no fault loads 2021-04-12 12:53:23 +08:00
um um: mm: check more comprehensively for stub changes 2021-04-12 12:52:40 +08:00
unicore32 Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
x86 x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) 2021-05-20 16:07:24 +08:00
xtensa xtensa: move coprocessor_flush to the .text section 2021-05-20 16:06:49 +08:00
.gitignore Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
Kconfig Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" 2021-03-16 16:43:47 +08:00