diff options
Diffstat (limited to 'arch/powerpc/lib/code-patching.c')
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 61 |
1 files changed, 10 insertions, 51 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 00c68e7fb11e..6edf0697a526 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -8,6 +8,7 @@ #include <linux/init.h> #include <linux/cpuhotplug.h> #include <linux/uaccess.h> +#include <linux/jump_label.h> #include <asm/tlbflush.h> #include <asm/page.h> @@ -32,7 +33,7 @@ static int __patch_instruction(u32 *exec_addr, ppc_inst_t instr, u32 *patch_addr return 0; failed: - return -EFAULT; + return -EPERM; } int raw_patch_instruction(u32 *addr, ppc_inst_t instr) @@ -78,6 +79,8 @@ static int text_area_cpu_down(unsigned int cpu) return 0; } +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poking_init_done); + /* * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and * we judge it as being preferable to a kernel that will crash later when @@ -88,6 +91,7 @@ void __init poking_init(void) BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke:online", text_area_cpu_up, text_area_cpu_down)); + static_branch_enable(&poking_init_done); } /* @@ -97,7 +101,7 @@ static int map_patch_area(void *addr, unsigned long text_poke_addr) { unsigned long pfn; - if (is_vmalloc_or_module_addr(addr)) + if (IS_ENABLED(CONFIG_MODULES) && is_vmalloc_or_module_addr(addr)) pfn = vmalloc_to_pfn(addr); else pfn = __pa_symbol(addr) >> PAGE_SHIFT; @@ -170,7 +174,7 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) * when text_poke_area is not ready, but we still need * to allow patching. We just do the plain old patching */ - if (!this_cpu_read(text_poke_area)) + if (!static_branch_likely(&poking_init_done)) return raw_patch_instruction(addr, instr); local_irq_save(flags); @@ -188,10 +192,12 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) #endif /* CONFIG_STRICT_KERNEL_RWX */ +__ro_after_init DEFINE_STATIC_KEY_FALSE(init_mem_is_free); + int patch_instruction(u32 *addr, ppc_inst_t instr) { /* Make sure we aren't patching a freed init section */ - if (system_state >= SYSTEM_FREEING_INITMEM && init_section_contains(addr, 4)) + if (static_branch_likely(&init_mem_is_free) && init_section_contains(addr, 4)) return 0; return do_patch_instruction(addr, instr); @@ -208,33 +214,6 @@ int patch_branch(u32 *addr, unsigned long target, int flags) return patch_instruction(addr, instr); } -bool is_offset_in_branch_range(long offset) -{ - /* - * Powerpc branch instruction is : - * - * 0 6 30 31 - * +---------+----------------+---+---+ - * | opcode | LI |AA |LK | - * +---------+----------------+---+---+ - * Where AA = 0 and LK = 0 - * - * LI is a signed 24 bits integer. The real branch offset is computed - * by: imm32 = SignExtend(LI:'0b00', 32); - * - * So the maximum forward branch should be: - * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc - * The maximum backward branch should be: - * (0xff800000 << 2) = 0xfe000000 = -0x2000000 - */ - return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); -} - -bool is_offset_in_cond_branch_range(long offset) -{ - return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); -} - /* * Helper to check if a given instruction is a conditional branch * Derived from the conditional checks in analyse_instr() @@ -257,26 +236,6 @@ bool is_conditional_branch(ppc_inst_t instr) } NOKPROBE_SYMBOL(is_conditional_branch); -int create_branch(ppc_inst_t *instr, const u32 *addr, - unsigned long target, int flags) -{ - long offset; - - *instr = ppc_inst(0); - offset = target; - if (! (flags & BRANCH_ABSOLUTE)) - offset = offset - (unsigned long)addr; - - /* Check we can represent the target in the instruction format */ - if (!is_offset_in_branch_range(offset)) - return 1; - - /* Mask out the flags and target, so they don't step on each other. */ - *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC)); - - return 0; -} - int create_cond_branch(ppc_inst_t *instr, const u32 *addr, unsigned long target, int flags) { |