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
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asm	x86/mm: Fix RESERVE_BRK() for older binutils	2022-06-13 10:15:04 +02:00
uapi/asm	S390:	2022-05-26 14:20:14 -07:00