From 9cc3d0c6915aee5140f8335d41bbc3ff1b79aa4e Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 14 Apr 2020 11:42:48 +0100 Subject: arm64: vdso: don't free unallocated pages The aarch32_vdso_pages[] array never has entries allocated in the C_VVAR or C_VDSO slots, and as the array is zero initialized these contain NULL. However in __aarch32_alloc_vdso_pages() when aarch32_alloc_kuser_vdso_page() fails we attempt to free the page whose struct page is at NULL, which is obviously nonsensical. This patch removes the erroneous page freeing. Fixes: 7c1deeeb0130 ("arm64: compat: VDSO setup for compat layer") Cc: # 5.3.x- Cc: Vincenzo Frascino Acked-by: Will Deacon Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/kernel/vdso.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 354b11e27c07..033a48f30dbb 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -260,18 +260,7 @@ static int __aarch32_alloc_vdso_pages(void) if (ret) return ret; - ret = aarch32_alloc_kuser_vdso_page(); - if (ret) { - unsigned long c_vvar = - (unsigned long)page_to_virt(aarch32_vdso_pages[C_VVAR]); - unsigned long c_vdso = - (unsigned long)page_to_virt(aarch32_vdso_pages[C_VDSO]); - - free_page(c_vvar); - free_page(c_vdso); - } - - return ret; + return aarch32_alloc_kuser_vdso_page(); } #else static int __aarch32_alloc_vdso_pages(void) -- cgit v1.2.3 From c9a4ef66450145a356a626c833d3d7b1668b3ded Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Tue, 14 Apr 2020 09:32:55 -0700 Subject: arm64: Delete the space separator in __emit_inst In assembly, many instances of __emit_inst(x) expand to a directive. In a few places __emit_inst(x) is used as an assembler macro argument. For example, in arch/arm64/kvm/hyp/entry.S ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN) expands to the following by the C preprocessor: alternative_insn nop, .inst (0xd500401f | ((0) << 16 | (4) << 5) | ((!!1) << 8)), 4, 1 Both comma and space are separators, with an exception that content inside a pair of parentheses/quotes is not split, so the clang integrated assembler splits the arguments to: nop, .inst, (0xd500401f | ((0) << 16 | (4) << 5) | ((!!1) << 8)), 4, 1 GNU as preprocesses the input with do_scrub_chars(). Its arm64 backend (along with many other non-x86 backends) sees: alternative_insn nop,.inst(0xd500401f|((0)<<16|(4)<<5)|((!!1)<<8)),4,1 # .inst(...) is parsed as one argument while its x86 backend sees: alternative_insn nop,.inst (0xd500401f|((0)<<16|(4)<<5)|((!!1)<<8)),4,1 # The extra space before '(' makes the whole .inst (...) parsed as two arguments The non-x86 backend's behavior is considered unintentional (https://sourceware.org/bugzilla/show_bug.cgi?id=25750). So drop the space separator inside `.inst (...)` to make the clang integrated assembler work. Suggested-by: Ilie Halip Signed-off-by: Fangrui Song Reviewed-by: Mark Rutland Link: https://github.com/ClangBuiltLinux/linux/issues/939 Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/sysreg.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index ebc622432831..c4ac0ac25a00 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -49,7 +49,9 @@ #ifndef CONFIG_BROKEN_GAS_INST #ifdef __ASSEMBLY__ -#define __emit_inst(x) .inst (x) +// The space separator is omitted so that __emit_inst(x) can be parsed as +// either an assembler directive or an assembler macro argument. +#define __emit_inst(x) .inst(x) #else #define __emit_inst(x) ".inst " __stringify((x)) "\n\t" #endif -- cgit v1.2.3