linux/arch/x86
Josh Poimboeuf e32683c6f7 x86/mm: Fix RESERVE_BRK() for older binutils
With binutils 2.26, RESERVE_BRK() causes a build failure:

  /tmp/ccnGOKZ5.s: Assembler messages:
  /tmp/ccnGOKZ5.s:98: Error: missing ')'
  /tmp/ccnGOKZ5.s:98: Error: missing ')'
  /tmp/ccnGOKZ5.s:98: Error: missing ')'
  /tmp/ccnGOKZ5.s:98: Error: junk at end of line, first unrecognized
  character is `U'

The problem is this line:

  RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE)

Specifically, the INIT_PGT_BUF_SIZE macro which (via PAGE_SIZE's use
_AC()) has a "1UL", which makes older versions of the assembler unhappy.
Unfortunately the _AC() macro doesn't work for inline asm.

Inline asm was only needed here to convince the toolchain to add the
STT_NOBITS flag.  However, if a C variable is placed in a section whose
name is prefixed with ".bss", GCC and Clang automatically set
STT_NOBITS.  In fact, ".bss..page_aligned" already relies on this trick.

So fix the build failure (and simplify the macro) by allocating the
variable in C.

Also, add NOLOAD to the ".brk" output section clause in the linker
script.  This is a failsafe in case the ".bss" prefix magic trick ever
stops working somehow.  If there's a section type mismatch, the GNU
linker will force the ".brk" output section to be STT_NOBITS.  The LLVM
linker will fail with a "section type mismatch" error.

Note this also changes the name of the variable from .brk.##name to
__brk_##name.  The variable names aren't actually used anywhere, so it's
harmless.

Fixes: a1e2c031ec ("x86/mm: Simplify RESERVE_BRK()")
Reported-by: Joe Damato <jdamato@fastly.com>
Reported-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Joe Damato <jdamato@fastly.com>
Link: https://lore.kernel.org/r/22d07a44c80d8e8e1e82b9a806ddc8c6bbb2606e.1654759036.git.jpoimboe@kernel.org
2022-06-13 10:15:04 +02:00
..
boot Follow-up tweaks for the EFI changes in v5.19 2022-06-03 13:39:30 -07:00
coco Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
configs x86/config: Make the x86 defconfigs a bit more usable 2022-03-27 20:58:35 +02:00
crypto crypto: x86 - eliminate anonymous module_init & module_exit 2022-04-08 16:13:31 +08:00
entry kernel-hardening updates for v5.19-rc1 2022-05-24 12:27:09 -07:00
events Two small perf updates: 2022-06-05 10:40:31 -07:00
hyperv hyperv-next for 5.17 2022-01-16 15:53:00 +02:00
ia32 x86: Remove a.out support 2022-04-11 18:04:27 +02:00
include x86/mm: Fix RESERVE_BRK() for older binutils 2022-06-13 10:15:04 +02:00
kernel x86/mm: Fix RESERVE_BRK() for older binutils 2022-06-13 10:15:04 +02:00
kvm * Fix syzkaller NULL pointer dereference 2022-06-08 09:16:31 -07:00
lib Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
math-emu x86/32: Remove lazy GS macros 2022-04-14 14:09:43 +02:00
mm virtio: replace arch_has_restricted_virtio_memory_access() 2022-06-06 08:22:01 +02:00
net bpf: Introduce bpf_arch_text_invalidate for bpf_prog_pack 2022-05-23 23:08:11 +02:00
pci pci-v5.19-changes 2022-05-27 15:25:10 -07:00
platform arch/x86: replace cpumask_weight with cpumask_empty where appropriate 2022-06-03 06:52:57 -07:00
power x86/cpu: Load microcode during restore_processor_state() 2022-04-19 19:37:05 +02:00
purgatory
ras
realmode Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
tools
um um: Fix out-of-bounds read in LDT setup 2022-05-27 09:03:41 +02:00
video
virt/vmx/tdx x86/tdx: Provide common base for SEAMCALL and TDCALL C wrappers 2022-04-07 08:27:50 -07:00
xen xen/virtio: Enable restricted memory access using Xen grant mappings 2022-06-06 16:07:30 +02:00
.gitignore
Kbuild x86/cc: Move arch/x86/{kernel/cc_platform.c => coco/core.c} 2022-02-23 18:25:58 +01:00
Kconfig virtio: replace arch_has_restricted_virtio_memory_access() 2022-06-06 08:22:01 +02:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug x86/Kconfig: Fix indentation of arch/x86/Kconfig.debug 2022-05-25 15:39:27 +02:00
Makefile Kbuild updates for v5.19 2022-05-26 12:09:50 -07:00
Makefile_32.cpu
Makefile.um