From 8cc28269b9574103aae9088a02a20929ec75f983 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 10 Nov 2018 16:14:59 +0100 Subject: parisc: Split out alternative live patching code Move the alternative implemenation coding to alternative.c and add code to patch modules while loading. Signed-off-by: Helge Deller --- arch/parisc/include/asm/alternative.h | 4 ++ arch/parisc/kernel/Makefile | 2 +- arch/parisc/kernel/alternative.c | 98 +++++++++++++++++++++++++++++++++++ arch/parisc/kernel/module.c | 14 +++++ arch/parisc/kernel/setup.c | 80 ---------------------------- 5 files changed, 117 insertions(+), 81 deletions(-) create mode 100644 arch/parisc/kernel/alternative.c (limited to 'arch') diff --git a/arch/parisc/include/asm/alternative.h b/arch/parisc/include/asm/alternative.h index bf485a94d0b4..793d8baa3a10 100644 --- a/arch/parisc/include/asm/alternative.h +++ b/arch/parisc/include/asm/alternative.h @@ -2,6 +2,7 @@ #ifndef __ASM_PARISC_ALTERNATIVE_H #define __ASM_PARISC_ALTERNATIVE_H +#define ALT_COND_ALWAYS 0x80 /* always replace instruction */ #define ALT_COND_NO_SMP 0x01 /* when running UP instead of SMP */ #define ALT_COND_NO_DCACHE 0x02 /* if system has no d-cache */ #define ALT_COND_NO_ICACHE 0x04 /* if system has no i-cache */ @@ -26,6 +27,9 @@ struct alt_instr { }; void set_kernel_text_rw(int enable_read_write); +void apply_alternatives_all(void); +void apply_alternatives(struct alt_instr *start, struct alt_instr *end, + const char *module_name); /* Alternative SMP implementation. */ #define ALTERNATIVE(cond, replacement) "!0:" \ diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile index e5de34d00b1a..8e5f1ab65c68 100644 --- a/arch/parisc/kernel/Makefile +++ b/arch/parisc/kernel/Makefile @@ -7,7 +7,7 @@ extra-y := head.o vmlinux.lds obj-y := cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \ pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \ - ptrace.o hardware.o inventory.o drivers.o \ + ptrace.o hardware.o inventory.o drivers.o alternative.o \ signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \ process.o processor.o pdc_cons.o pdc_chassis.o unwind.o diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c new file mode 100644 index 000000000000..bf2274e01a96 --- /dev/null +++ b/arch/parisc/kernel/alternative.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Alternative live-patching for parisc. + * Copyright (C) 2018 Helge Deller + * + */ + +#include +#include +#include + +#include + +static int no_alternatives; +static int __init setup_no_alternatives(char *str) +{ + no_alternatives = 1; + return 1; +} +__setup("no-alternatives", setup_no_alternatives); + +void __init_or_module apply_alternatives(struct alt_instr *start, + struct alt_instr *end, const char *module_name) +{ + struct alt_instr *entry; + int index = 0, applied = 0; + int num_cpus = num_online_cpus(); + + for (entry = start; entry < end; entry++, index++) { + + u32 *from, len, cond, replacement; + + from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); + len = entry->len; + cond = entry->cond; + replacement = entry->replacement; + + WARN_ON(!cond); + + if (cond != ALT_COND_ALWAYS && no_alternatives) + continue; + + pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", + index, cond, len, from, replacement); + + if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1)) + continue; + if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0)) + continue; + if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0)) + continue; + + /* + * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit + * set (bit #61, big endian), we have to flush and sync every + * time IO-PDIR is changed in Ike/Astro. + */ + if ((cond & ALT_COND_NO_IOC_FDC) && + (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)) + continue; + + /* Want to replace pdtlb by a pdtlb,l instruction? */ + if (replacement == INSN_PxTLB) { + replacement = *from; + if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */ + replacement |= (1 << 10); /* set el bit */ + } + + /* + * Replace instruction with NOPs? + * For long distance insert a branch instruction instead. + */ + if (replacement == INSN_NOP && len > 1) + replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */ + + pr_debug("Do %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", + index, cond, len, from, replacement); + + /* Replace instruction */ + *from = replacement; + applied++; + } + + pr_info("%s%salternatives: applied %d out of %d patches\n", + module_name ? : "", module_name ? " " : "", + applied, index); +} + + +void __init apply_alternatives_all(void) +{ + set_kernel_text_rw(1); + + apply_alternatives((struct alt_instr *) &__alt_instructions, + (struct alt_instr *) &__alt_instructions_end, NULL); + + set_kernel_text_rw(0); +} diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index b5b3cb00f1fb..43778420614b 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -877,6 +877,8 @@ int module_finalize(const Elf_Ehdr *hdr, int i; unsigned long nsyms; const char *strtab = NULL; + const Elf_Shdr *s; + char *secstrings; Elf_Sym *newptr, *oldptr; Elf_Shdr *symhdr = NULL; #ifdef DEBUG @@ -948,6 +950,18 @@ int module_finalize(const Elf_Ehdr *hdr, nsyms = newptr - (Elf_Sym *)symhdr->sh_addr; DEBUGP("NEW num_symtab %lu\n", nsyms); symhdr->sh_size = nsyms * sizeof(Elf_Sym); + + /* find .altinstructions section */ + secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { + void *aseg = (void *) s->sh_addr; + char *secname = secstrings + s->sh_name; + + if (!strcmp(".altinstructions", secname)) + /* patch .altinstructions */ + apply_alternatives(aseg, aseg + s->sh_size, me->name); + } + return 0; } diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c index cd227f1cf629..2b108ee3b217 100644 --- a/arch/parisc/kernel/setup.c +++ b/arch/parisc/kernel/setup.c @@ -305,86 +305,6 @@ static int __init parisc_init_resources(void) return 0; } -static int no_alternatives __initdata; -static int __init setup_no_alternatives(char *str) -{ - no_alternatives = 1; - return 1; -} -__setup("no-alternatives", setup_no_alternatives); - -static void __init apply_alternatives_all(void) -{ - struct alt_instr *entry; - int index = 0, applied = 0; - - - pr_info("alternatives: %spatching kernel code\n", - no_alternatives ? "NOT " : ""); - if (no_alternatives) - return; - - set_kernel_text_rw(1); - - for (entry = (struct alt_instr *) &__alt_instructions; - entry < (struct alt_instr *) &__alt_instructions_end; - entry++, index++) { - - u32 *from, len, cond, replacement; - - from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); - len = entry->len; - cond = entry->cond; - replacement = entry->replacement; - - WARN_ON(!cond); - pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", - index, cond, len, from, replacement); - - if ((cond & ALT_COND_NO_SMP) && (num_online_cpus() != 1)) - continue; - if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0)) - continue; - if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0)) - continue; - - /* - * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit - * set (bit #61, big endian), we have to flush and sync every - * time IO-PDIR is changed in Ike/Astro. - */ - if ((cond & ALT_COND_NO_IOC_FDC) && - (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)) - continue; - - /* Want to replace pdtlb by a pdtlb,l instruction? */ - if (replacement == INSN_PxTLB) { - replacement = *from; - if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */ - replacement |= (1 << 10); /* set el bit */ - } - - /* - * Replace instruction with NOPs? - * For long distance insert a branch instruction instead. - */ - if (replacement == INSN_NOP && len > 1) - replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */ - - pr_debug("Do %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n", - index, cond, len, from, replacement); - - /* Replace instruction */ - *from = replacement; - applied++; - } - - pr_info("alternatives: applied %d out of %d patches\n", applied, index); - - set_kernel_text_rw(0); -} - - extern void gsc_init(void); extern void processor_init(void); extern void ccio_init(void); -- cgit v1.2.1