From b0b49f2673f011cad7deeabf7a683b388c351278 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 13 Mar 2014 16:01:26 -0700 Subject: x86, vdso: Remove compat vdso support The compat vDSO is a complicated hack that's needed to maintain compatibility with a small range of glibc versions. This removes it and replaces it with a much simpler hack: a config option to disable the 32-bit vDSO by default. This also changes the default value of CONFIG_COMPAT_VDSO to n -- users configuring kernels from scratch almost certainly want that choice. Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/4bb4690899106eb11430b1186d5cc66ca9d1660c.1394751608.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/elf.h | 4 ---- arch/x86/include/asm/fixmap.h | 8 -------- arch/x86/include/asm/vdso.h | 5 +---- 3 files changed, 1 insertion(+), 16 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 9c999c1674fa..2c71182d30ef 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -281,16 +281,12 @@ do { \ #define STACK_RND_MASK (0x7ff) -#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO)) - #define ARCH_DLINFO ARCH_DLINFO_IA32(vdso_enabled) /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */ #else /* CONFIG_X86_32 */ -#define VDSO_HIGH_BASE 0xffffe000U /* CONFIG_COMPAT_VDSO address */ - /* 1GB for 64bit, 8MB for 32bit */ #define STACK_RND_MASK (test_thread_flag(TIF_ADDR32) ? 0x7ff : 0x3fffff) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 7252cd339175..2377f5618fb7 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -40,15 +40,8 @@ */ extern unsigned long __FIXADDR_TOP; #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP) - -#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO) -#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1) #else #define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE) - -/* Only covers 32bit vsyscalls currently. Need another set for 64bit. */ -#define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL) -#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE) #endif @@ -74,7 +67,6 @@ extern unsigned long __FIXADDR_TOP; enum fixed_addresses { #ifdef CONFIG_X86_32 FIX_HOLE, - FIX_VDSO, #else VSYSCALL_LAST_PAGE, VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index fddb53d63915..5594e84d65d9 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -2,8 +2,6 @@ #define _ASM_X86_VDSO_H #if defined CONFIG_X86_32 || defined CONFIG_COMPAT -extern const char VDSO32_PRELINK[]; - /* * Given a pointer to the vDSO image, find the pointer to VDSO32_name * as that symbol is defined in the vDSO sources or linker script. @@ -11,8 +9,7 @@ extern const char VDSO32_PRELINK[]; #define VDSO32_SYMBOL(base, name) \ ({ \ extern const char VDSO32_##name[]; \ - (void __user *)(VDSO32_##name - VDSO32_PRELINK + \ - (unsigned long)(base)); \ + (void __user *)(VDSO32_##name + (unsigned long)(base)); \ }) #endif -- cgit v1.2.1 From 7dda038756704b3562187b29c81f86de935148c6 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 13 Mar 2014 16:01:27 -0700 Subject: x86_32, mm: Remove user bit from identity map PDE The only reason that the user bit was set was to support userspace access to the compat vDSO in the fixmap. The compat vDSO is gone, so the user bit can be removed. Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/e240a977f3c7cbd525a091fd6521499ec4b8e94f.1394751608.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/pgtable_types.h | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 1aa9ccd43223..757f9c40321b 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -214,13 +214,8 @@ #ifdef CONFIG_X86_64 #define __PAGE_KERNEL_IDENT_LARGE_EXEC __PAGE_KERNEL_LARGE_EXEC #else -/* - * For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection - * bits are combined, this will alow user to access the high address mapped - * VDSO in the presence of CONFIG_COMPAT_VDSO - */ #define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */ -#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */ +#define PDE_IDENT_ATTR 0x063 /* PRESENT+RW+DIRTY+ACCESSED */ #define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */ #endif -- cgit v1.2.1 From d2312e3379d581d2c3603357a0181046448e1de3 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 17 Mar 2014 23:22:01 +0100 Subject: x86, vdso: Make vsyscall_gtod_data handling x86 generic This patch move the vsyscall_gtod_data handling out of vsyscall_64.c into an additonal file vsyscall_gtod.c to make the functionality available for x86 32 bit kernel. It also adds a new vsyscall_32.c which setup the VVAR page. Reviewed-by: Andy Lutomirski Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/clocksource.h | 4 ---- arch/x86/include/asm/vvar.h | 12 +++++++++--- 2 files changed, 9 insertions(+), 7 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h index 16a57f4ed64d..eda81dc0f4ae 100644 --- a/arch/x86/include/asm/clocksource.h +++ b/arch/x86/include/asm/clocksource.h @@ -3,8 +3,6 @@ #ifndef _ASM_X86_CLOCKSOURCE_H #define _ASM_X86_CLOCKSOURCE_H -#ifdef CONFIG_X86_64 - #define VCLOCK_NONE 0 /* No vDSO clock available. */ #define VCLOCK_TSC 1 /* vDSO should use vread_tsc. */ #define VCLOCK_HPET 2 /* vDSO should use vread_hpet. */ @@ -14,6 +12,4 @@ struct arch_clocksource_data { int vclock_mode; }; -#endif /* CONFIG_X86_64 */ - #endif /* _ASM_X86_CLOCKSOURCE_H */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index d76ac40da206..0a534eac5f56 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -16,9 +16,6 @@ * you mess up, the linker will catch it.) */ -/* Base address of vvars. This is not ABI. */ -#define VVAR_ADDRESS (-10*1024*1024 - 4096) - #if defined(__VVAR_KERNEL_LDS) /* The kernel linker script defines its own magic to put vvars in the @@ -29,6 +26,15 @@ #else +extern char __vvar_page; + +/* Base address of vvars. This is not ABI. */ +#ifdef CONFIG_X86_64 +#define VVAR_ADDRESS (-10*1024*1024 - 4096) +#else +#define VVAR_ADDRESS (&__vvar_page) +#endif + #define DECLARE_VVAR(offset, type, name) \ static type const * const vvaraddr_ ## name = \ (void *)(VVAR_ADDRESS + (offset)); -- cgit v1.2.1 From ef721987aef0cc0abba08c88810f2155f76b0b1f Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 17 Mar 2014 23:22:07 +0100 Subject: x86, vdso: Introduce VVAR marco for vdso32 This patch revamps the vvar.h for introduce the VVAR macro for vdso32. Reviewed-by: Andy Lutomirski Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-8-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vvar.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 0a534eac5f56..52c79ffc3161 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -26,6 +26,15 @@ #else +#ifdef BUILD_VDSO32 + +#define DECLARE_VVAR(offset, type, name) \ + extern type vvar_ ## name __attribute__((visibility("hidden"))); + +#define VVAR(name) (vvar_ ## name) + +#else + extern char __vvar_page; /* Base address of vvars. This is not ABI. */ @@ -39,12 +48,13 @@ extern char __vvar_page; static type const * const vvaraddr_ ## name = \ (void *)(VVAR_ADDRESS + (offset)); +#define VVAR(name) (*vvaraddr_ ## name) +#endif + #define DEFINE_VVAR(type, name) \ type name \ __attribute__((section(".vvar_" #name), aligned(16))) __visible -#define VVAR(name) (*vvaraddr_ ## name) - #endif /* DECLARE_VVAR(offset, type, name) */ -- cgit v1.2.1 From b4b541a610c4db8643b36030ee5012203ca65778 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 17 Mar 2014 23:22:08 +0100 Subject: x86, vdso: Patch alternatives in the 32-bit VDSO We need the alternatives mechanism for rdtsc_barrier() to work. Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-9-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vdso.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 5594e84d65d9..f8605e61b0c5 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -28,4 +28,6 @@ extern const char vdso32_int80_start, vdso32_int80_end; extern const char vdso32_syscall_start, vdso32_syscall_end; extern const char vdso32_sysenter_start, vdso32_sysenter_end; +void __init patch_vdso32(void *vdso, size_t len); + #endif /* _ASM_X86_VDSO_H */ -- cgit v1.2.1 From 7a59ed415f5b57469e22e41fc4188d5399e0b194 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 17 Mar 2014 23:22:09 +0100 Subject: x86, vdso: Add 32 bit VDSO time support for 32 bit kernel This patch add the time support for 32 bit a VDSO to a 32 bit kernel. For 32 bit programs running on a 32 bit kernel, the same mechanism is used as for 64 bit programs running on a 64 bit kernel. Reviewed-by: Andy Lutomirski Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-10-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vdso.h | 5 +++++ arch/x86/include/asm/vdso32.h | 11 +++++++++++ 2 files changed, 16 insertions(+) create mode 100644 arch/x86/include/asm/vdso32.h (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index f8605e61b0c5..bde435998f3a 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -2,6 +2,11 @@ #define _ASM_X86_VDSO_H #if defined CONFIG_X86_32 || defined CONFIG_COMPAT + +#include + +extern const char VDSO32_PRELINK[]; + /* * Given a pointer to the vDSO image, find the pointer to VDSO32_name * as that symbol is defined in the vDSO sources or linker script. diff --git a/arch/x86/include/asm/vdso32.h b/arch/x86/include/asm/vdso32.h new file mode 100644 index 000000000000..7efb7018406e --- /dev/null +++ b/arch/x86/include/asm/vdso32.h @@ -0,0 +1,11 @@ +#ifndef _ASM_X86_VDSO32_H +#define _ASM_X86_VDSO32_H + +#define VDSO_BASE_PAGE 0 +#define VDSO_VVAR_PAGE 1 +#define VDSO_HPET_PAGE 2 +#define VDSO_PAGES 3 +#define VDSO_PREV_PAGES 2 +#define VDSO_OFFSET(x) ((x) * PAGE_SIZE) + +#endif -- cgit v1.2.1 From 7c03156f34d113f885f045d8fb8cc3efd9e64751 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 17 Mar 2014 23:22:10 +0100 Subject: x86, vdso: Add 32 bit VDSO time support for 64 bit kernel This patch add the VDSO time support for the IA32 Emulation Layer. Due the nature of the kernel headers and the LP64 compiler where the size of a long and a pointer differs against a 32 bit compiler, there is some type hacking necessary for optimal performance. The vsyscall_gtod_data struture must be a rearranged to serve 32- and 64-bit code access at the same time: - The seqcount_t was replaced by an unsigned, this makes the vsyscall_gtod_data intedepend of kernel configuration and internal functions. - All kernel internal structures are replaced by fix size elements which works for 32- and 64-bit access - The inner struct clock was removed to pack the whole struct. The "unsigned seq" would be handled by functions derivated from seqcount_t. Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-11-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vgtod.h | 71 +++++++++++++++++++++++++++++++++++--------- arch/x86/include/asm/vvar.h | 5 ++++ 2 files changed, 62 insertions(+), 14 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h index 46e24d36b7da..3c3366c2e37f 100644 --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -1,30 +1,73 @@ #ifndef _ASM_X86_VGTOD_H #define _ASM_X86_VGTOD_H -#include +#include #include +#ifdef BUILD_VDSO32_64 +typedef u64 gtod_long_t; +#else +typedef unsigned long gtod_long_t; +#endif +/* + * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time + * so be carefull by modifying this structure. + */ struct vsyscall_gtod_data { - seqcount_t seq; + unsigned seq; - struct { /* extract of a clocksource struct */ - int vclock_mode; - cycle_t cycle_last; - cycle_t mask; - u32 mult; - u32 shift; - } clock; + int vclock_mode; + cycle_t cycle_last; + cycle_t mask; + u32 mult; + u32 shift; /* open coded 'struct timespec' */ - time_t wall_time_sec; u64 wall_time_snsec; + gtod_long_t wall_time_sec; + gtod_long_t monotonic_time_sec; u64 monotonic_time_snsec; - time_t monotonic_time_sec; + gtod_long_t wall_time_coarse_sec; + gtod_long_t wall_time_coarse_nsec; + gtod_long_t monotonic_time_coarse_sec; + gtod_long_t monotonic_time_coarse_nsec; - struct timezone sys_tz; - struct timespec wall_time_coarse; - struct timespec monotonic_time_coarse; + int tz_minuteswest; + int tz_dsttime; }; extern struct vsyscall_gtod_data vsyscall_gtod_data; +static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s) +{ + unsigned ret; + +repeat: + ret = ACCESS_ONCE(s->seq); + if (unlikely(ret & 1)) { + cpu_relax(); + goto repeat; + } + smp_rmb(); + return ret; +} + +static inline int gtod_read_retry(const struct vsyscall_gtod_data *s, + unsigned start) +{ + smp_rmb(); + return unlikely(s->seq != start); +} + +static inline void gtod_write_begin(struct vsyscall_gtod_data *s) +{ + ++s->seq; + smp_wmb(); +} + +static inline void gtod_write_end(struct vsyscall_gtod_data *s) +{ + smp_wmb(); + ++s->seq; +} + #endif /* _ASM_X86_VGTOD_H */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 52c79ffc3161..081d909bc495 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -16,6 +16,9 @@ * you mess up, the linker will catch it.) */ +#ifndef _ASM_X86_VVAR_H +#define _ASM_X86_VVAR_H + #if defined(__VVAR_KERNEL_LDS) /* The kernel linker script defines its own magic to put vvars in the @@ -64,3 +67,5 @@ DECLARE_VVAR(16, int, vgetcpu_mode) DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data) #undef DECLARE_VVAR + +#endif -- cgit v1.2.1 From b67e612cef1e5964efc6fa99fb7ad3d31c4db01a Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 20 Mar 2014 15:01:21 -0700 Subject: x86: Load the 32-bit vdso in place, just like the 64-bit vdsos This replaces a decent amount of incomprehensible and buggy code with much more straightforward code. It also brings the 32-bit vdso more in line with the 64-bit vdsos, so maybe someday they can share even more code. This wastes a small amount of kernel .data and .text space, but it avoids a couple of allocations on startup, so it should be more or less a wash memory-wise. Signed-off-by: Andy Lutomirski Cc: Stefani Seibold Link: http://lkml.kernel.org/r/b8093933fad09ce181edb08a61dcd5d2592e9814.1395352498.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vdso.h | 8 -------- 1 file changed, 8 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index bde435998f3a..0301d78bb910 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -25,14 +25,6 @@ extern const char VDSO32_PRELINK[]; extern void __user __kernel_sigreturn; extern void __user __kernel_rt_sigreturn; -/* - * These symbols are defined by vdso32.S to mark the bounds - * of the ELF DSO images included therein. - */ -extern const char vdso32_int80_start, vdso32_int80_end; -extern const char vdso32_syscall_start, vdso32_syscall_end; -extern const char vdso32_sysenter_start, vdso32_sysenter_end; - void __init patch_vdso32(void *vdso, size_t len); #endif /* _ASM_X86_VDSO_H */ -- cgit v1.2.1 From 9e6f450f946d35d585798da268d45c679632fe05 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 20 Mar 2014 18:57:18 -0700 Subject: x86, vdso: Move more vdso definitions into vdso.h This fixes the Xen build and gets rid of a silly header file. Signed-off-by: Andy Lutomirski Cc: Stefani Seibold Link: http://lkml.kernel.org/r/1df77311795aff75f5742c787d277518314a38d3.1395366931.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vdso.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 0301d78bb910..7622a65a969e 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -1,10 +1,46 @@ #ifndef _ASM_X86_VDSO_H #define _ASM_X86_VDSO_H +#include +#include + +#ifdef __ASSEMBLER__ + +#define DEFINE_VDSO_IMAGE(symname, filename) \ +__PAGE_ALIGNED_DATA ; \ + .globl symname##_start, symname##_end ; \ + .align PAGE_SIZE ; \ + symname##_start: ; \ + .incbin filename ; \ + symname##_end: ; \ + .align PAGE_SIZE /* extra data here leaks to userspace. */ ; \ + \ +.previous ; \ + \ + .globl symname##_pages ; \ + .bss ; \ + .align 8 ; \ + .type symname##_pages, @object ; \ + symname##_pages: ; \ + .zero (symname##_end - symname##_start + PAGE_SIZE - 1) / PAGE_SIZE * (BITS_PER_LONG / 8) ; \ + .size symname##_pages, .-symname##_pages + +#else + +#define DECLARE_VDSO_IMAGE(symname) \ + extern char symname##_start[], symname##_end[]; \ + extern struct page *symname##_pages[] + #if defined CONFIG_X86_32 || defined CONFIG_COMPAT #include +DECLARE_VDSO_IMAGE(vdso32_int80); +#ifdef CONFIG_COMPAT +DECLARE_VDSO_IMAGE(vdso32_syscall); +#endif +DECLARE_VDSO_IMAGE(vdso32_sysenter); + extern const char VDSO32_PRELINK[]; /* @@ -27,4 +63,6 @@ extern void __user __kernel_rt_sigreturn; void __init patch_vdso32(void *vdso, size_t len); +#endif /* __ASSEMBLER__ */ + #endif /* _ASM_X86_VDSO_H */ -- cgit v1.2.1 From 3c1b63b9e4862fb16352a0646439c2dd6d9e0e5c Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 20 Mar 2014 18:57:19 -0700 Subject: x86, vdso: Finish removing VDSO32_PRELINK It's a declaration of a nonexistent symbol. We can get rid of the 64-bit versions, too, but that's more intrusive. Signed-off-by: Andy Lutomirski Cc: Stefani Seibold Link: http://lkml.kernel.org/r/2ce2ce18447d8a0b78d44a278a066b6c0af06b32.1395366931.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/vdso.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 7622a65a969e..d1dc55404ff1 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -41,8 +41,6 @@ DECLARE_VDSO_IMAGE(vdso32_syscall); #endif DECLARE_VDSO_IMAGE(vdso32_sysenter); -extern const char VDSO32_PRELINK[]; - /* * Given a pointer to the vDSO image, find the pointer to VDSO32_name * as that symbol is defined in the vDSO sources or linker script. -- cgit v1.2.1