|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v10 6/6] xen: use DEFINE_SYMBOL as required
Use DEFINE_SYMBOL and the two static inline functions that come with it for comparisons and subtractions of: _start, _end, _stext, _etext, _srodata, _erodata, _sinittext, _einittext Use explicit casts to uintptr_t when it is not possible to use the provided static inline functions. M3CM: Rule-18.2: Subtraction between pointers shall only be applied to pointers that address elements of the same array Since we are changing the body of is_kernel_text and friends, take the opportunity to remove the leading underscores in the local variables names, which are violationg namespace rules. Also make the local p__ variable const. https://wiki.sei.cmu.edu/confluence/display/c/ARR36-C.+Do+not+subtract+or+compare+two+pointers+that+do+not+refer+to+the+same+array QAVerify: 2761 Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx> CC: JBeulich@xxxxxxxx CC: andrew.cooper3@xxxxxxxxxx --- Changes in v10: - new patch --- xen/arch/arm/alternative.c | 5 +++-- xen/arch/arm/arm32/livepatch.c | 14 +++++++++++++- xen/arch/arm/arm64/livepatch.c | 14 +++++++++++++- xen/arch/arm/livepatch.c | 16 ++++++++++++++-- xen/arch/arm/mm.c | 4 ++-- xen/arch/arm/setup.c | 5 +++-- xen/arch/x86/setup.c | 6 ++++-- xen/include/asm-arm/grant_table.h | 3 ++- xen/include/xen/kernel.h | 37 +++++++++++++++++++++---------------- 9 files changed, 75 insertions(+), 29 deletions(-) diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c index cef9cca..7a1fe5a 100644 --- a/xen/arch/arm/alternative.c +++ b/xen/arch/arm/alternative.c @@ -192,7 +192,7 @@ static int __apply_alternatives_multi_stop(void *unused) int ret; struct alt_region region; mfn_t xen_mfn = virt_to_mfn(_start); - paddr_t xen_size = _end - _start; + paddr_t xen_size = xen_diff(_start, _end); unsigned int xen_order = get_order_from_bytes(xen_size); void *xenmap; @@ -210,7 +210,8 @@ static int __apply_alternatives_multi_stop(void *unused) region.begin = __alt_instructions; region.end = (struct alt_instr *)__alt_instructions_end; - ret = __apply_alternatives(®ion, xenmap - (void *)_start); + ret = __apply_alternatives(®ion, (uintptr_t)xenmap - + (uintptr_t)_start); /* The patching is not expected to fail during boot. */ BUG_ON(ret != 0); diff --git a/xen/arch/arm/arm32/livepatch.c b/xen/arch/arm/arm32/livepatch.c index 41378a5..5f7390e 100644 --- a/xen/arch/arm/arm32/livepatch.c +++ b/xen/arch/arm/arm32/livepatch.c @@ -56,7 +56,19 @@ void arch_livepatch_apply(struct livepatch_func *func) else insn = 0xe1a00000; /* mov r0, r0 */ - new_ptr = func->old_addr - (void *)_start + vmap_of_xen_text; + /* + * We need to calculate the offset of the address from _start, and + * apply that to our own map, to find where we have this mapped. + * Doing these kind of games directly with pointers is contrary to + * the C rules for what pointers may be compared and computed. So + * we do the offset calculation with integers, which is always + * legal. The subsequent addition of the offset to the + * vmap_of_xen_text pointer is legal because the computed pointer is + * indeed a valid part of the object referred to by vmap_of_xen_text + * - namely, the byte array of our mapping of the Xen text. + */ + new_ptr = ((uintptr_t)func->old_addr, - (uintptr_t)_start) + + vmap_of_xen_text; len = len / sizeof(uint32_t); /* PATCH! */ diff --git a/xen/arch/arm/arm64/livepatch.c b/xen/arch/arm/arm64/livepatch.c index 2247b92..362235c 100644 --- a/xen/arch/arm/arm64/livepatch.c +++ b/xen/arch/arm/arm64/livepatch.c @@ -43,7 +43,19 @@ void arch_livepatch_apply(struct livepatch_func *func) /* Verified in livepatch_verify_distance. */ ASSERT(insn != AARCH64_BREAK_FAULT); - new_ptr = func->old_addr - (void *)_start + vmap_of_xen_text; + /* + * We need to calculate the offset of the address from _start, and + * apply that to our own map, to find where we have this mapped. + * Doing these kind of games directly with pointers is contrary to + * the C rules for what pointers may be compared and computed. So + * we do the offset calculation with integers, which is always + * legal. The subsequent addition of the offset to the + * vmap_of_xen_text pointer is legal because the computed pointer is + * indeed a valid part of the object referred to by vmap_of_xen_text + * - namely, the byte array of our mapping of the Xen text. + */ + new_ptr = ((uintptr_t)func->old_addr, - (uintptr_t)_start) + + vmap_of_xen_text; len = len / sizeof(uint32_t); /* PATCH! */ diff --git a/xen/arch/arm/livepatch.c b/xen/arch/arm/livepatch.c index 279d52c..af4411a 100644 --- a/xen/arch/arm/livepatch.c +++ b/xen/arch/arm/livepatch.c @@ -27,7 +27,7 @@ int arch_livepatch_quiesce(void) return -EINVAL; text_mfn = virt_to_mfn(_start); - text_order = get_order_from_bytes(_end - _start); + text_order = get_order_from_bytes(xen_diff(_start, _end)); /* * The text section is read-only. So re-map Xen to be able to patch @@ -78,7 +78,19 @@ void arch_livepatch_revert(const struct livepatch_func *func) uint32_t *new_ptr; unsigned int len; - new_ptr = func->old_addr - (void *)_start + vmap_of_xen_text; + /* + * We need to calculate the offset of the address from _start, and + * apply that to our own map, to find where we have this mapped. + * Doing these kind of games directly with pointers is contrary to + * the C rules for what pointers may be compared and computed. So + * we do the offset calculation with integers, which is always + * legal. The subsequent addition of the offset to the + * vmap_of_xen_text pointer is legal because the computed pointer is + * indeed a valid part of the object referred to by vmap_of_xen_text + * - namely, the byte array of our mapping of the Xen text. + */ + new_ptr = ((uintptr_t)func->old_addr, - (uintptr_t)_start) + + vmap_of_xen_text; len = livepatch_insn_len(func); memcpy(new_ptr, func->opaque, len); diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 9f31e81..7f9a309 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -1084,8 +1084,8 @@ static void set_pte_flags_on_range(const char *p, unsigned long l, enum mg mg) ASSERT(!((unsigned long) p & ~PAGE_MASK)); ASSERT(!(l & ~PAGE_MASK)); - for ( i = (p - _start) / PAGE_SIZE; - i < (p + l - _start) / PAGE_SIZE; + for ( i = ((uintptr_t)p - (uintptr_t)_start) / PAGE_SIZE; + i < ((uintptr_t)p + l - (uintptr_t)_start) / PAGE_SIZE; i++ ) { pte = xen_xenmap[i]; diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index 444857a..8d43943 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -772,8 +772,9 @@ void __init start_xen(unsigned long boot_phys_offset, /* Register Xen's load address as a boot module. */ xen_bootmodule = add_boot_module(BOOTMOD_XEN, - (paddr_t)(uintptr_t)(_start + boot_phys_offset), - (paddr_t)(uintptr_t)(_end - _start + 1), false); + (paddr_t)(_start + boot_phys_offset), + (paddr_t)(xen_diff(_start, _end) + 1), + false); BUG_ON(!xen_bootmodule); setup_pagetables(boot_phys_offset); diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index b024339..7ede826 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -975,7 +975,8 @@ void __init noreturn __start_xen(unsigned long mbi_p) * respective reserve_e820_ram() invocation below. */ mod[mbi->mods_count].mod_start = virt_to_mfn(_stext); - mod[mbi->mods_count].mod_end = __2M_rwdata_end - _stext; + mod[mbi->mods_count].mod_end = (uintptr_t)__2M_rwdata_end - + (uintptr_t) _stext; } modules_headroom = bzimage_headroom(bootstrap_map(mod), mod->mod_end); @@ -1070,7 +1071,8 @@ void __init noreturn __start_xen(unsigned long mbi_p) * data until after we have switched to the relocated pagetables! */ barrier(); - move_memory(e + XEN_IMG_OFFSET, XEN_IMG_OFFSET, _end - _start, 1); + move_memory(e + XEN_IMG_OFFSET, XEN_IMG_OFFSET, + xen_diff(_start, _end), 1); /* Walk initial pagetables, relocating page directory entries. */ pl4e = __va(__pa(idle_pg_table)); diff --git a/xen/include/asm-arm/grant_table.h b/xen/include/asm-arm/grant_table.h index 816e3c6..1097791 100644 --- a/xen/include/asm-arm/grant_table.h +++ b/xen/include/asm-arm/grant_table.h @@ -31,7 +31,8 @@ void gnttab_mark_dirty(struct domain *d, mfn_t mfn); * enough space for a large grant table */ #define gnttab_dom0_frames() \ - min_t(unsigned int, opt_max_grant_frames, PFN_DOWN(_etext - _stext)) + min_t(unsigned int, opt_max_grant_frames, \ + PFN_DOWN(text_diff(_stext, _etext))) #define gnttab_init_arch(gt) \ ({ \ diff --git a/xen/include/xen/kernel.h b/xen/include/xen/kernel.h index 548b64d..15ace6d 100644 --- a/xen/include/xen/kernel.h +++ b/xen/include/xen/kernel.h @@ -65,28 +65,33 @@ 1; \ }) -extern char _start[], _end[], start[]; -#define is_kernel(p) ({ \ - char *__p = (char *)(unsigned long)(p); \ - (__p >= _start) && (__p < _end); \ +extern char start[]; +DEFINE_SYMBOL(char, xen, _start, _end); +#define is_kernel(p) ({ \ + const char *p__ = (const char *)(unsigned long)(p); \ + ((uintptr_t)p__ >= (uintptr_t)_start && \ + xen_lt(p__, _end)); \ }) -extern char _stext[], _etext[]; -#define is_kernel_text(p) ({ \ - char *__p = (char *)(unsigned long)(p); \ - (__p >= _stext) && (__p < _etext); \ +DEFINE_SYMBOL(char, text, _stext, _etext); +#define is_kernel_text(p) ({ \ + const char *p__ = (const char *)(unsigned long)(p); \ + ((uintptr_t)p__ >= (uintptr_t) _stext && \ + text_lt(p__, _etext)); \ }) -extern const char _srodata[], _erodata[]; -#define is_kernel_rodata(p) ({ \ - const char *__p = (const char *)(unsigned long)(p); \ - (__p >= _srodata) && (__p < _erodata); \ +DEFINE_SYMBOL(char, rodata, _srodata, _erodata); +#define is_kernel_rodata(p) ({ \ + const char *p__ = (const char *)(unsigned long)(p); \ + ((uintptr_t)p__ >= (uintptr_t)_srodata && \ + rodata_lt(p__, _erodata)); \ }) -extern char _sinittext[], _einittext[]; -#define is_kernel_inittext(p) ({ \ - char *__p = (char *)(unsigned long)(p); \ - (__p >= _sinittext) && (__p < _einittext); \ +DEFINE_SYMBOL(char, inittext, _sinittext, _einittext); +#define is_kernel_inittext(p) ({ \ + const char *p__ = (const char *)(unsigned long)(p); \ + ((uintptr_t)p__ >= (uintptr_t) _sinittext && \ + inittext_lt(p__, _einittext)); \ }) extern enum system_state { -- 1.9.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |