| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Michael Ellerman | 2001 | 57.07% | 5 | 14.29% |
| Jordan Niethe | 655 | 18.68% | 10 | 28.57% |
| Balbir Singh | 520 | 14.83% | 1 | 2.86% |
| Christophe Leroy | 118 | 3.37% | 7 | 20.00% |
| Anju T | 94 | 2.68% | 2 | 5.71% |
| Kevin Hao | 48 | 1.37% | 1 | 2.86% |
| Mike Rapoport | 26 | 0.74% | 1 | 2.86% |
| Josh Poimboeuf | 19 | 0.54% | 1 | 2.86% |
| Steven Rostedt | 9 | 0.26% | 1 | 2.86% |
| Naveen N. Rao | 8 | 0.23% | 1 | 2.86% |
| Andrea Righi | 3 | 0.09% | 1 | 2.86% |
| Thomas Gleixner | 2 | 0.06% | 1 | 2.86% |
| Linus Torvalds | 1 | 0.03% | 1 | 2.86% |
| Benjamin Herrenschmidt | 1 | 0.03% | 1 | 2.86% |
| Russell Currey | 1 | 0.03% | 1 | 2.86% |
| Total | 3506 | 35 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright 2008 Michael Ellerman, IBM Corporation. */ #include <linux/kernel.h> #include <linux/kprobes.h> #include <linux/vmalloc.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/cpuhotplug.h> #include <linux/slab.h> #include <linux/uaccess.h> #include <asm/tlbflush.h> #include <asm/page.h> #include <asm/code-patching.h> #include <asm/setup.h> #include <asm/inst.h> static int __patch_instruction(struct ppc_inst *exec_addr, struct ppc_inst instr, struct ppc_inst *patch_addr) { if (!ppc_inst_prefixed(instr)) { u32 val = ppc_inst_val(instr); __put_kernel_nofault(patch_addr, &val, u32, failed); } else { u64 val = ppc_inst_as_ulong(instr); __put_kernel_nofault(patch_addr, &val, u64, failed); } asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr), "r" (exec_addr)); return 0; failed: return -EFAULT; } int raw_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr) { return __patch_instruction(addr, instr, addr); } #ifdef CONFIG_STRICT_KERNEL_RWX static DEFINE_PER_CPU(struct vm_struct *, text_poke_area); static int text_area_cpu_up(unsigned int cpu) { struct vm_struct *area; area = get_vm_area(PAGE_SIZE, VM_ALLOC); if (!area) { WARN_ONCE(1, "Failed to create text area for cpu %d\n", cpu); return -1; } this_cpu_write(text_poke_area, area); return 0; } static int text_area_cpu_down(unsigned int cpu) { free_vm_area(this_cpu_read(text_poke_area)); return 0; } /* * Run as a late init call. This allows all the boot time patching to be done * simply by patching the code, and then we're called here prior to * mark_rodata_ro(), which happens after all init calls are run. 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 someone tries * to use patch_instruction(). */ static int __init setup_text_poke_area(void) { BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke:online", text_area_cpu_up, text_area_cpu_down)); return 0; } late_initcall(setup_text_poke_area); /* * This can be called for kernel text or a module. */ static int map_patch_area(void *addr, unsigned long text_poke_addr) { unsigned long pfn; int err; if (is_vmalloc_or_module_addr(addr)) pfn = vmalloc_to_pfn(addr); else pfn = __pa_symbol(addr) >> PAGE_SHIFT; err = map_kernel_page(text_poke_addr, (pfn << PAGE_SHIFT), PAGE_KERNEL); pr_devel("Mapped addr %lx with pfn %lx:%d\n", text_poke_addr, pfn, err); if (err) return -1; return 0; } static inline int unmap_patch_area(unsigned long addr) { pte_t *ptep; pmd_t *pmdp; pud_t *pudp; p4d_t *p4dp; pgd_t *pgdp; pgdp = pgd_offset_k(addr); if (unlikely(!pgdp)) return -EINVAL; p4dp = p4d_offset(pgdp, addr); if (unlikely(!p4dp)) return -EINVAL; pudp = pud_offset(p4dp, addr); if (unlikely(!pudp)) return -EINVAL; pmdp = pmd_offset(pudp, addr); if (unlikely(!pmdp)) return -EINVAL; ptep = pte_offset_kernel(pmdp, addr); if (unlikely(!ptep)) return -EINVAL; pr_devel("clearing mm %p, pte %p, addr %lx\n", &init_mm, ptep, addr); /* * In hash, pte_clear flushes the tlb, in radix, we have to */ pte_clear(&init_mm, addr, ptep); flush_tlb_kernel_range(addr, addr + PAGE_SIZE); return 0; } static int do_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr) { int err; struct ppc_inst *patch_addr = NULL; unsigned long flags; unsigned long text_poke_addr; unsigned long kaddr = (unsigned long)addr; /* * During early early boot patch_instruction is called * 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)) return raw_patch_instruction(addr, instr); local_irq_save(flags); text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr; if (map_patch_area(addr, text_poke_addr)) { err = -1; goto out; } patch_addr = (struct ppc_inst *)(text_poke_addr + (kaddr & ~PAGE_MASK)); __patch_instruction(addr, instr, patch_addr); err = unmap_patch_area(text_poke_addr); if (err) pr_warn("failed to unmap %lx\n", text_poke_addr); out: local_irq_restore(flags); return err; } #else /* !CONFIG_STRICT_KERNEL_RWX */ static int do_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr) { return raw_patch_instruction(addr, instr); } #endif /* CONFIG_STRICT_KERNEL_RWX */ int patch_instruction(struct ppc_inst *addr, struct ppc_inst instr) { /* Make sure we aren't patching a freed init section */ if (init_mem_is_free && init_section_contains(addr, 4)) { pr_debug("Skipping init section patching addr: 0x%px\n", addr); return 0; } return do_patch_instruction(addr, instr); } NOKPROBE_SYMBOL(patch_instruction); int patch_branch(struct ppc_inst *addr, unsigned long target, int flags) { struct ppc_inst instr; create_branch(&instr, addr, target, 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)); } /* * Helper to check if a given instruction is a conditional branch * Derived from the conditional checks in analyse_instr() */ bool is_conditional_branch(struct ppc_inst instr) { unsigned int opcode = ppc_inst_primary_opcode(instr); if (opcode == 16) /* bc, bca, bcl, bcla */ return true; if (opcode == 19) { switch ((ppc_inst_val(instr) >> 1) & 0x3ff) { case 16: /* bclr, bclrl */ case 528: /* bcctr, bcctrl */ case 560: /* bctar, bctarl */ return true; } } return false; } NOKPROBE_SYMBOL(is_conditional_branch); int create_branch(struct ppc_inst *instr, const struct ppc_inst *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(struct ppc_inst *instr, const struct ppc_inst *addr, unsigned long target, int flags) { long offset; offset = target; if (! (flags & BRANCH_ABSOLUTE)) offset = offset - (unsigned long)addr; /* Check we can represent the target in the instruction format */ if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3) return 1; /* Mask out the flags and target, so they don't step on each other. */ *instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC)); return 0; } static unsigned int branch_opcode(struct ppc_inst instr) { return ppc_inst_primary_opcode(instr) & 0x3F; } static int instr_is_branch_iform(struct ppc_inst instr) { return branch_opcode(instr) == 18; } static int instr_is_branch_bform(struct ppc_inst instr) { return branch_opcode(instr) == 16; } int instr_is_relative_branch(struct ppc_inst instr) { if (ppc_inst_val(instr) & BRANCH_ABSOLUTE) return 0; return instr_is_branch_iform(instr) || instr_is_branch_bform(instr); } int instr_is_relative_link_branch(struct ppc_inst instr) { return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK); } static unsigned long branch_iform_target(const struct ppc_inst *instr) { signed long imm; imm = ppc_inst_val(*instr) & 0x3FFFFFC; /* If the top bit of the immediate value is set this is negative */ if (imm & 0x2000000) imm -= 0x4000000; if ((ppc_inst_val(*instr) & BRANCH_ABSOLUTE) == 0) imm += (unsigned long)instr; return (unsigned long)imm; } static unsigned long branch_bform_target(const struct ppc_inst *instr) { signed long imm; imm = ppc_inst_val(*instr) & 0xFFFC; /* If the top bit of the immediate value is set this is negative */ if (imm & 0x8000) imm -= 0x10000; if ((ppc_inst_val(*instr) & BRANCH_ABSOLUTE) == 0) imm += (unsigned long)instr; return (unsigned long)imm; } unsigned long branch_target(const struct ppc_inst *instr) { if (instr_is_branch_iform(ppc_inst_read(instr))) return branch_iform_target(instr); else if (instr_is_branch_bform(ppc_inst_read(instr))) return branch_bform_target(instr); return 0; } int instr_is_branch_to_addr(const struct ppc_inst *instr, unsigned long addr) { if (instr_is_branch_iform(ppc_inst_read(instr)) || instr_is_branch_bform(ppc_inst_read(instr))) return branch_target(instr) == addr; return 0; } int translate_branch(struct ppc_inst *instr, const struct ppc_inst *dest, const struct ppc_inst *src) { unsigned long target; target = branch_target(src); if (instr_is_branch_iform(ppc_inst_read(src))) return create_branch(instr, dest, target, ppc_inst_val(ppc_inst_read(src))); else if (instr_is_branch_bform(ppc_inst_read(src))) return create_cond_branch(instr, dest, target, ppc_inst_val(ppc_inst_read(src))); return 1; } #ifdef CONFIG_PPC_BOOK3E_64 void __patch_exception(int exc, unsigned long addr) { extern unsigned int interrupt_base_book3e; unsigned int *ibase = &interrupt_base_book3e; /* Our exceptions vectors start with a NOP and -then- a branch * to deal with single stepping from userspace which stops on * the second instruction. Thus we need to patch the second * instruction of the exception, not the first one */ patch_branch((struct ppc_inst *)(ibase + (exc / 4) + 1), addr, 0); } #endif #ifdef CONFIG_CODE_PATCHING_SELFTEST static void __init test_trampoline(void) { asm ("nop;\n"); } #define check(x) \ if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__); static void __init test_branch_iform(void) { int err; struct ppc_inst instr; unsigned long addr; addr = (unsigned long)&instr; /* The simplest case, branch to self, no flags */ check(instr_is_branch_iform(ppc_inst(0x48000000))); /* All bits of target set, and flags */ check(instr_is_branch_iform(ppc_inst(0x4bffffff))); /* High bit of opcode set, which is wrong */ check(!instr_is_branch_iform(ppc_inst(0xcbffffff))); /* Middle bits of opcode set, which is wrong */ check(!instr_is_branch_iform(ppc_inst(0x7bffffff))); /* Simplest case, branch to self with link */ check(instr_is_branch_iform(ppc_inst(0x48000001))); /* All bits of targets set */ check(instr_is_branch_iform(ppc_inst(0x4bfffffd))); /* Some bits of targets set */ check(instr_is_branch_iform(ppc_inst(0x4bff00fd))); /* Must be a valid branch to start with */ check(!instr_is_branch_iform(ppc_inst(0x7bfffffd))); /* Absolute branch to 0x100 */ instr = ppc_inst(0x48000103); check(instr_is_branch_to_addr(&instr, 0x100)); /* Absolute branch to 0x420fc */ instr = ppc_inst(0x480420ff); check(instr_is_branch_to_addr(&instr, 0x420fc)); /* Maximum positive relative branch, + 20MB - 4B */ instr = ppc_inst(0x49fffffc); check(instr_is_branch_to_addr(&instr, addr + 0x1FFFFFC)); /* Smallest negative relative branch, - 4B */ instr = ppc_inst(0x4bfffffc); check(instr_is_branch_to_addr(&instr, addr - 4)); /* Largest negative relative branch, - 32 MB */ instr = ppc_inst(0x4a000000); check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); /* Branch to self, with link */ err = create_branch(&instr, &instr, addr, BRANCH_SET_LINK); check(instr_is_branch_to_addr(&instr, addr)); /* Branch to self - 0x100, with link */ err = create_branch(&instr, &instr, addr - 0x100, BRANCH_SET_LINK); check(instr_is_branch_to_addr(&instr, addr - 0x100)); /* Branch to self + 0x100, no link */ err = create_branch(&instr, &instr, addr + 0x100, 0); check(instr_is_branch_to_addr(&instr, addr + 0x100)); /* Maximum relative negative offset, - 32 MB */ err = create_branch(&instr, &instr, addr - 0x2000000, BRANCH_SET_LINK); check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); /* Out of range relative negative offset, - 32 MB + 4*/ err = create_branch(&instr, &instr, addr - 0x2000004, BRANCH_SET_LINK); check(err); /* Out of range relative positive offset, + 32 MB */ err = create_branch(&instr, &instr, addr + 0x2000000, BRANCH_SET_LINK); check(err); /* Unaligned target */ err = create_branch(&instr, &instr, addr + 3, BRANCH_SET_LINK); check(err); /* Check flags are masked correctly */ err = create_branch(&instr, &instr, addr, 0xFFFFFFFC); check(instr_is_branch_to_addr(&instr, addr)); check(ppc_inst_equal(instr, ppc_inst(0x48000000))); } static void __init test_create_function_call(void) { struct ppc_inst *iptr; unsigned long dest; struct ppc_inst instr; /* Check we can create a function call */ iptr = (struct ppc_inst *)ppc_function_entry(test_trampoline); dest = ppc_function_entry(test_create_function_call); create_branch(&instr, iptr, dest, BRANCH_SET_LINK); patch_instruction(iptr, instr); check(instr_is_branch_to_addr(iptr, dest)); } static void __init test_branch_bform(void) { int err; unsigned long addr; struct ppc_inst *iptr, instr; unsigned int flags; iptr = &instr; addr = (unsigned long)iptr; /* The simplest case, branch to self, no flags */ check(instr_is_branch_bform(ppc_inst(0x40000000))); /* All bits of target set, and flags */ check(instr_is_branch_bform(ppc_inst(0x43ffffff))); /* High bit of opcode set, which is wrong */ check(!instr_is_branch_bform(ppc_inst(0xc3ffffff))); /* Middle bits of opcode set, which is wrong */ check(!instr_is_branch_bform(ppc_inst(0x7bffffff))); /* Absolute conditional branch to 0x100 */ instr = ppc_inst(0x43ff0103); check(instr_is_branch_to_addr(&instr, 0x100)); /* Absolute conditional branch to 0x20fc */ instr = ppc_inst(0x43ff20ff); check(instr_is_branch_to_addr(&instr, 0x20fc)); /* Maximum positive relative conditional branch, + 32 KB - 4B */ instr = ppc_inst(0x43ff7ffc); check(instr_is_branch_to_addr(&instr, addr + 0x7FFC)); /* Smallest negative relative conditional branch, - 4B */ instr = ppc_inst(0x43fffffc); check(instr_is_branch_to_addr(&instr, addr - 4)); /* Largest negative relative conditional branch, - 32 KB */ instr = ppc_inst(0x43ff8000); check(instr_is_branch_to_addr(&instr, addr - 0x8000)); /* All condition code bits set & link */ flags = 0x3ff000 | BRANCH_SET_LINK; /* Branch to self */ err = create_cond_branch(&instr, iptr, addr, flags); check(instr_is_branch_to_addr(&instr, addr)); /* Branch to self - 0x100 */ err = create_cond_branch(&instr, iptr, addr - 0x100, flags); check(instr_is_branch_to_addr(&instr, addr - 0x100)); /* Branch to self + 0x100 */ err = create_cond_branch(&instr, iptr, addr + 0x100, flags); check(instr_is_branch_to_addr(&instr, addr + 0x100)); /* Maximum relative negative offset, - 32 KB */ err = create_cond_branch(&instr, iptr, addr - 0x8000, flags); check(instr_is_branch_to_addr(&instr, addr - 0x8000)); /* Out of range relative negative offset, - 32 KB + 4*/ err = create_cond_branch(&instr, iptr, addr - 0x8004, flags); check(err); /* Out of range relative positive offset, + 32 KB */ err = create_cond_branch(&instr, iptr, addr + 0x8000, flags); check(err); /* Unaligned target */ err = create_cond_branch(&instr, iptr, addr + 3, flags); check(err); /* Check flags are masked correctly */ err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC); check(instr_is_branch_to_addr(&instr, addr)); check(ppc_inst_equal(instr, ppc_inst(0x43FF0000))); } static void __init test_translate_branch(void) { unsigned long addr; void *p, *q; struct ppc_inst instr; void *buf; buf = vmalloc(PAGE_ALIGN(0x2000000 + 1)); check(buf); if (!buf) return; /* Simple case, branch to self moved a little */ p = buf; addr = (unsigned long)p; patch_branch(p, addr, 0); check(instr_is_branch_to_addr(p, addr)); q = p + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(q, addr)); /* Maximum negative case, move b . to addr + 32 MB */ p = buf; addr = (unsigned long)p; patch_branch(p, addr, 0); q = buf + 0x2000000; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000))); /* Maximum positive case, move x to x - 32 MB + 4 */ p = buf + 0x2000000; addr = (unsigned long)p; patch_branch(p, addr, 0); q = buf + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc))); /* Jump to x + 16 MB moved to x + 20 MB */ p = buf; addr = 0x1000000 + (unsigned long)buf; patch_branch(p, addr, BRANCH_SET_LINK); q = buf + 0x1400000; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); /* Jump to x + 16 MB moved to x - 16 MB + 4 */ p = buf + 0x1000000; addr = 0x2000000 + (unsigned long)buf; patch_branch(p, addr, 0); q = buf + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); /* Conditional branch tests */ /* Simple case, branch to self moved a little */ p = buf; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0); patch_instruction(p, instr); check(instr_is_branch_to_addr(p, addr)); q = buf + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(q, addr)); /* Maximum negative case, move b . to addr + 32 KB */ p = buf; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0xFFFFFFFC); patch_instruction(p, instr); q = buf + 0x8000; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000))); /* Maximum positive case, move x to x - 32 KB + 4 */ p = buf + 0x8000; addr = (unsigned long)p; create_cond_branch(&instr, p, addr, 0xFFFFFFFC); patch_instruction(p, instr); q = buf + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc))); /* Jump to x + 12 KB moved to x + 20 KB */ p = buf; addr = 0x3000 + (unsigned long)buf; create_cond_branch(&instr, p, addr, BRANCH_SET_LINK); patch_instruction(p, instr); q = buf + 0x5000; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); /* Jump to x + 8 KB moved to x - 8 KB + 4 */ p = buf + 0x2000; addr = 0x4000 + (unsigned long)buf; create_cond_branch(&instr, p, addr, 0); patch_instruction(p, instr); q = buf + 4; translate_branch(&instr, q, p); patch_instruction(q, instr); check(instr_is_branch_to_addr(p, addr)); check(instr_is_branch_to_addr(q, addr)); /* Free the buffer we were using */ vfree(buf); } #ifdef CONFIG_PPC64 static void __init test_prefixed_patching(void) { extern unsigned int code_patching_test1[]; extern unsigned int code_patching_test1_expected[]; extern unsigned int end_code_patching_test1[]; __patch_instruction((struct ppc_inst *)code_patching_test1, ppc_inst_prefix(OP_PREFIX << 26, 0x00000000), (struct ppc_inst *)code_patching_test1); check(!memcmp(code_patching_test1, code_patching_test1_expected, sizeof(unsigned int) * (end_code_patching_test1 - code_patching_test1))); } #else static inline void test_prefixed_patching(void) {} #endif static int __init test_code_patching(void) { printk(KERN_DEBUG "Running code patching self-tests ...\n"); test_branch_iform(); test_branch_bform(); test_create_function_call(); test_translate_branch(); test_prefixed_patching(); return 0; } late_initcall(test_code_patching); #endif /* CONFIG_CODE_PATCHING_SELFTEST */
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