x86: make TASK_SIZE_MAX usable from assembly code (a1d826d4) · Commits · 戴 / test

For 64-bit the only thing missing was a strategic _AC, and for 32-bit we need to use __PAGE_OFFSET instead of PAGE_OFFSET in the TASK_SIZE definition to escape the explicit unsigned long cast. This just works because __PAGE_OFFSET is defined using _AC itself and thus never needs the cast anyway. Signed-off-by:

Christoph Hellwig <hch@lst.de> Reviewed-by:

Kees Cook <keescook@chromium.org> Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

arch/x86/include/asm/page_32_types.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -44,8 +44,8 @@
		/*
		* User space process size: 3GB (default).
		*/
		#define IA32_PAGE_OFFSET PAGE_OFFSET
		#define TASK_SIZE PAGE_OFFSET
		#define IA32_PAGE_OFFSET __PAGE_OFFSET
		#define TASK_SIZE __PAGE_OFFSET
		#define TASK_SIZE_LOW TASK_SIZE
		#define TASK_SIZE_MAX TASK_SIZE
		#define DEFAULT_MAP_WINDOW TASK_SIZE

arch/x86/include/asm/page_64_types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -76,7 +76,7 @@
		*
		* With page table isolation enabled, we map the LDT in ... [stay tuned]
		*/
		#define TASK_SIZE_MAX ((1UL << __VIRTUAL_MASK_SHIFT) - PAGE_SIZE)
		#define TASK_SIZE_MAX ((_AC(1,UL) << __VIRTUAL_MASK_SHIFT) - PAGE_SIZE)

		#define DEFAULT_MAP_WINDOW ((1UL << 47) - PAGE_SIZE)

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