diff options
Diffstat (limited to 'arch/powerpc/lib/code-patching.c')
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 247 |
1 files changed, 222 insertions, 25 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index b00112d7ad46..f84e0337cc02 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -17,18 +17,17 @@ #include <asm/tlb.h> #include <asm/tlbflush.h> #include <asm/page.h> -#include <asm/code-patching.h> +#include <asm/text-patching.h> #include <asm/inst.h> -static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr) +static int __patch_mem(void *exec_addr, unsigned long val, void *patch_addr, bool is_dword) { - if (!ppc_inst_prefixed(instr)) { - u32 val = ppc_inst_val(instr); + if (!IS_ENABLED(CONFIG_PPC64) || likely(!is_dword)) { + /* For big endian correctness: plain address would use the wrong half */ + u32 val32 = val; - __put_kernel_nofault(patch_addr, &val, u32, failed); + __put_kernel_nofault(patch_addr, &val32, u32, failed); } else { - u64 val = ppc_inst_as_ulong(instr); - __put_kernel_nofault(patch_addr, &val, u64, failed); } @@ -38,12 +37,16 @@ static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr return 0; failed: + mb(); /* sync */ return -EPERM; } int raw_patch_instruction(u32 *addr, ppc_inst_t instr) { - return __patch_instruction(addr, instr, addr); + if (ppc_inst_prefixed(instr)) + return __patch_mem(addr, ppc_inst_as_ulong(instr), addr, true); + else + return __patch_mem(addr, ppc_inst_val(instr), addr, false); } struct patch_context { @@ -105,7 +108,7 @@ static int text_area_cpu_up(unsigned int cpu) unsigned long addr; int err; - area = get_vm_area(PAGE_SIZE, VM_ALLOC); + area = get_vm_area(PAGE_SIZE, 0); if (!area) { WARN_ONCE(1, "Failed to create text area for cpu %d\n", cpu); @@ -204,9 +207,6 @@ void __init poking_init(void) { int ret; - if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) - return; - if (mm_patch_enabled()) ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke_mm:online", @@ -227,7 +227,7 @@ void __init poking_init(void) static unsigned long get_patch_pfn(void *addr) { - if (IS_ENABLED(CONFIG_MODULES) && is_vmalloc_or_module_addr(addr)) + if (IS_ENABLED(CONFIG_EXECMEM) && is_vmalloc_or_module_addr(addr)) return vmalloc_to_pfn(addr); else return __pa_symbol(addr) >> PAGE_SHIFT; @@ -278,7 +278,7 @@ static void unmap_patch_area(unsigned long addr) flush_tlb_kernel_range(addr, addr + PAGE_SIZE); } -static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr) +static int __do_patch_mem_mm(void *addr, unsigned long val, bool is_dword) { int err; u32 *patch_addr; @@ -307,11 +307,7 @@ static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr) orig_mm = start_using_temp_mm(patching_mm); - err = __patch_instruction(addr, instr, patch_addr); - - /* hwsync performed by __patch_instruction (sync) if successful */ - if (err) - mb(); /* sync */ + err = __patch_mem(addr, val, patch_addr, is_dword); /* context synchronisation performed by __patch_instruction (isync or exception) */ stop_using_temp_mm(patching_mm, orig_mm); @@ -328,7 +324,7 @@ static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr) return err; } -static int __do_patch_instruction(u32 *addr, ppc_inst_t instr) +static int __do_patch_mem(void *addr, unsigned long val, bool is_dword) { int err; u32 *patch_addr; @@ -345,7 +341,7 @@ static int __do_patch_instruction(u32 *addr, ppc_inst_t instr) if (radix_enabled()) asm volatile("ptesync": : :"memory"); - err = __patch_instruction(addr, instr, patch_addr); + err = __patch_mem(addr, val, patch_addr, is_dword); pte_clear(&init_mm, text_poke_addr, pte); flush_tlb_kernel_range(text_poke_addr, text_poke_addr + PAGE_SIZE); @@ -353,7 +349,7 @@ static int __do_patch_instruction(u32 *addr, ppc_inst_t instr) return err; } -int patch_instruction(u32 *addr, ppc_inst_t instr) +static int patch_mem(void *addr, unsigned long val, bool is_dword) { int err; unsigned long flags; @@ -365,19 +361,220 @@ int patch_instruction(u32 *addr, ppc_inst_t instr) */ if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) || !static_branch_likely(&poking_init_done)) - return raw_patch_instruction(addr, instr); + return __patch_mem(addr, val, addr, is_dword); local_irq_save(flags); if (mm_patch_enabled()) - err = __do_patch_instruction_mm(addr, instr); + err = __do_patch_mem_mm(addr, val, is_dword); else - err = __do_patch_instruction(addr, instr); + err = __do_patch_mem(addr, val, is_dword); local_irq_restore(flags); return err; } + +#ifdef CONFIG_PPC64 + +int patch_instruction(u32 *addr, ppc_inst_t instr) +{ + if (ppc_inst_prefixed(instr)) + return patch_mem(addr, ppc_inst_as_ulong(instr), true); + else + return patch_mem(addr, ppc_inst_val(instr), false); +} NOKPROBE_SYMBOL(patch_instruction); +int patch_uint(void *addr, unsigned int val) +{ + if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned int))) + return -EINVAL; + + return patch_mem(addr, val, false); +} +NOKPROBE_SYMBOL(patch_uint); + +int patch_ulong(void *addr, unsigned long val) +{ + if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned long))) + return -EINVAL; + + return patch_mem(addr, val, true); +} +NOKPROBE_SYMBOL(patch_ulong); + +#else + +int patch_instruction(u32 *addr, ppc_inst_t instr) +{ + return patch_mem(addr, ppc_inst_val(instr), false); +} +NOKPROBE_SYMBOL(patch_instruction) + +#endif + +static int patch_memset64(u64 *addr, u64 val, size_t count) +{ + for (u64 *end = addr + count; addr < end; addr++) + __put_kernel_nofault(addr, &val, u64, failed); + + return 0; + +failed: + return -EPERM; +} + +static int patch_memset32(u32 *addr, u32 val, size_t count) +{ + for (u32 *end = addr + count; addr < end; addr++) + __put_kernel_nofault(addr, &val, u32, failed); + + return 0; + +failed: + return -EPERM; +} + +static int __patch_instructions(u32 *patch_addr, u32 *code, size_t len, bool repeat_instr) +{ + unsigned long start = (unsigned long)patch_addr; + int err; + + /* Repeat instruction */ + if (repeat_instr) { + ppc_inst_t instr = ppc_inst_read(code); + + if (ppc_inst_prefixed(instr)) { + u64 val = ppc_inst_as_ulong(instr); + + err = patch_memset64((u64 *)patch_addr, val, len / 8); + } else { + u32 val = ppc_inst_val(instr); + + err = patch_memset32(patch_addr, val, len / 4); + } + } else { + err = copy_to_kernel_nofault(patch_addr, code, len); + } + + smp_wmb(); /* smp write barrier */ + flush_icache_range(start, start + len); + return err; +} + +/* + * A page is mapped and instructions that fit the page are patched. + * Assumes 'len' to be (PAGE_SIZE - offset_in_page(addr)) or below. + */ +static int __do_patch_instructions_mm(u32 *addr, u32 *code, size_t len, bool repeat_instr) +{ + struct mm_struct *patching_mm, *orig_mm; + unsigned long pfn = get_patch_pfn(addr); + unsigned long text_poke_addr; + spinlock_t *ptl; + u32 *patch_addr; + pte_t *pte; + int err; + + patching_mm = __this_cpu_read(cpu_patching_context.mm); + text_poke_addr = __this_cpu_read(cpu_patching_context.addr); + patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr)); + + pte = get_locked_pte(patching_mm, text_poke_addr, &ptl); + if (!pte) + return -ENOMEM; + + __set_pte_at(patching_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0); + + /* order PTE update before use, also serves as the hwsync */ + asm volatile("ptesync" ::: "memory"); + + /* order context switch after arbitrary prior code */ + isync(); + + orig_mm = start_using_temp_mm(patching_mm); + + kasan_disable_current(); + err = __patch_instructions(patch_addr, code, len, repeat_instr); + kasan_enable_current(); + + /* context synchronisation performed by __patch_instructions */ + stop_using_temp_mm(patching_mm, orig_mm); + + pte_clear(patching_mm, text_poke_addr, pte); + /* + * ptesync to order PTE update before TLB invalidation done + * by radix__local_flush_tlb_page_psize (in _tlbiel_va) + */ + local_flush_tlb_page_psize(patching_mm, text_poke_addr, mmu_virtual_psize); + + pte_unmap_unlock(pte, ptl); + + return err; +} + +/* + * A page is mapped and instructions that fit the page are patched. + * Assumes 'len' to be (PAGE_SIZE - offset_in_page(addr)) or below. + */ +static int __do_patch_instructions(u32 *addr, u32 *code, size_t len, bool repeat_instr) +{ + unsigned long pfn = get_patch_pfn(addr); + unsigned long text_poke_addr; + u32 *patch_addr; + pte_t *pte; + int err; + + text_poke_addr = (unsigned long)__this_cpu_read(cpu_patching_context.addr) & PAGE_MASK; + patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr)); + + pte = __this_cpu_read(cpu_patching_context.pte); + __set_pte_at(&init_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0); + /* See ptesync comment in radix__set_pte_at() */ + if (radix_enabled()) + asm volatile("ptesync" ::: "memory"); + + err = __patch_instructions(patch_addr, code, len, repeat_instr); + + pte_clear(&init_mm, text_poke_addr, pte); + flush_tlb_kernel_range(text_poke_addr, text_poke_addr + PAGE_SIZE); + + return err; +} + +/* + * Patch 'addr' with 'len' bytes of instructions from 'code'. + * + * If repeat_instr is true, the same instruction is filled for + * 'len' bytes. + */ +int patch_instructions(u32 *addr, u32 *code, size_t len, bool repeat_instr) +{ + while (len > 0) { + unsigned long flags; + size_t plen; + int err; + + plen = min_t(size_t, PAGE_SIZE - offset_in_page(addr), len); + + local_irq_save(flags); + if (mm_patch_enabled()) + err = __do_patch_instructions_mm(addr, code, plen, repeat_instr); + else + err = __do_patch_instructions(addr, code, plen, repeat_instr); + local_irq_restore(flags); + if (err) + return err; + + len -= plen; + addr = (u32 *)((unsigned long)addr + plen); + if (!repeat_instr) + code = (u32 *)((unsigned long)code + plen); + } + + return 0; +} +NOKPROBE_SYMBOL(patch_instructions); + int patch_branch(u32 *addr, unsigned long target, int flags) { ppc_inst_t instr; |