Greetings, GCC 7 introduced the -Wstringop-overflow flag to detect buffer overflows in calls to string handling functions [1][2]. Due to the way ``empty_zero_page'' is declared in arch/sparc/include/setup.h, this causes a warning to trigger at compile time in the function mem_init(), which is subsequently converted to an error. The attached patch fixes this issue and aligns the declaration of empty_zero_page to that of other architectures. Thank you. Cheers, Orlando. [1] https://gcc.gnu.org/ml/gcc-patches/2016-10/msg02308.html [2] https://gcc.gnu.org/gcc-7/changes.html
diff -rupN linux-4.11.1-pristine/arch/sparc/include/asm/pgtable_32.h linux-4.11.1-modified/arch/sparc/include/asm/pgtable_32.h --- linux-4.11.1-pristine/arch/sparc/include/asm/pgtable_32.h 2017-05-14 08:06:16.000000000 -0400 +++ linux-4.11.1-modified/arch/sparc/include/asm/pgtable_32.h 2017-05-16 14:08:21.220784497 -0400 @@ -91,9 +91,9 @@ extern unsigned long pfn_base; * ZERO_PAGE is a global shared page that is always zero: used * for zero-mapped memory areas etc.. */ -extern unsigned long empty_zero_page; +extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; -#define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page)) +#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) /* * In general all page table modifications should use the V8 atomic diff -rupN linux-4.11.1-pristine/arch/sparc/include/asm/setup.h linux-4.11.1-modified/arch/sparc/include/asm/setup.h --- linux-4.11.1-pristine/arch/sparc/include/asm/setup.h 2017-05-14 08:06:16.000000000 -0400 +++ linux-4.11.1-modified/arch/sparc/include/asm/setup.h 2017-05-16 14:05:31.887441581 -0400 @@ -16,7 +16,7 @@ extern char reboot_command[]; */ extern unsigned char boot_cpu_id; -extern unsigned long empty_zero_page; +extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; extern int serial_console; static inline int con_is_present(void) diff -rupN linux-4.11.1-pristine/arch/sparc/mm/init_32.c linux-4.11.1-modified/arch/sparc/mm/init_32.c --- linux-4.11.1-pristine/arch/sparc/mm/init_32.c 2017-05-14 08:06:16.000000000 -0400 +++ linux-4.11.1-modified/arch/sparc/mm/init_32.c 2017-05-16 14:06:02.497443313 -0400 @@ -290,7 +290,7 @@ void __init mem_init(void) /* Saves us work later. */ - memset((void *)&empty_zero_page, 0, PAGE_SIZE); + memset((void *)empty_zero_page, 0, PAGE_SIZE); i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5); i += 1;
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