From 8cbb2b50ee2dcb082675237eaaa48fe8479f8aa5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 25 Aug 2022 10:25:05 +0200 Subject: asm-generic: Conditionally enable do_softirq_own_stack() via Kconfig. Remove the CONFIG_PREEMPT_RT symbol from the ifdef around do_softirq_own_stack() and move it to Kconfig instead. Enable softirq stacks based on SOFTIRQ_ON_OWN_STACK which depends on HAVE_SOFTIRQ_ON_OWN_STACK and its default value is set to !PREEMPT_RT. This ensures that softirq stacks are not used on PREEMPT_RT and avoids a 'select' statement on an option which has a 'depends' statement. Link: https://lore.kernel.org/YvN5E%2FPrHfUhggr7@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Arnd Bergmann --- include/asm-generic/softirq_stack.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/softirq_stack.h b/include/asm-generic/softirq_stack.h index d3e2d81656e0..2a67aed9ac52 100644 --- a/include/asm-generic/softirq_stack.h +++ b/include/asm-generic/softirq_stack.h @@ -2,7 +2,7 @@ #ifndef __ASM_GENERIC_SOFTIRQ_STACK_H #define __ASM_GENERIC_SOFTIRQ_STACK_H -#if defined(CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK) && !defined(CONFIG_PREEMPT_RT) +#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK void do_softirq_own_stack(void); #else static inline void do_softirq_own_stack(void) -- cgit v1.2.3 From 13b0566962914e167cb3238fbe29ced618f07a27 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 22 Sep 2022 22:57:15 +0100 Subject: vmlinux.lds.h: CFI: Reduce alignment of jump-table to function alignment Due to undocumented, hysterical raisins on x86, the CFI jump-table sections in .text are needlessly aligned to PMD_SIZE in the vmlinux linker script. When compiling a CFI-enabled arm64 kernel with a 64KiB page-size, a PMD maps 512MiB of virtual memory and so the .text section increases to a whopping 940MiB and blows the final Image up to 960MiB. Others report a link failure. Since the CFI jump-table requires only instruction alignment, reduce the alignment directives to function alignment for parity with other parts of the .text section. This reduces the size of the .text section for the aforementioned 64KiB page size arm64 kernel to 19MiB for a much more reasonable total Image size of 39MiB. Cc: Sami Tolvanen Cc: Mark Rutland Cc: "Mohan Rao .vanimina" Cc: Kees Cook Cc: Nathan Chancellor Cc: Link: https://lore.kernel.org/all/CAL_GTzigiNOMYkOPX1KDnagPhJtFNqSK=1USNbS0wUL4PW6-Uw@mail.gmail.com/ Fixes: cf68fffb66d6 ("add support for Clang CFI") Reviewed-by: Mark Rutland Tested-by: Mark Rutland Reviewed-by: Sami Tolvanen Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20220922215715.13345-1-will@kernel.org Signed-off-by: Will Deacon --- include/asm-generic/vmlinux.lds.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 7515a465ec03..7c90b1ab3e00 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -543,10 +543,9 @@ */ #ifdef CONFIG_CFI_CLANG #define TEXT_CFI_JT \ - . = ALIGN(PMD_SIZE); \ + ALIGN_FUNCTION(); \ __cfi_jt_start = .; \ *(.text..L.cfi.jumptable .text..L.cfi.jumptable.*) \ - . = ALIGN(PMD_SIZE); \ __cfi_jt_end = .; #else #define TEXT_CFI_JT -- cgit v1.2.3