From 82992fc70f98dee091faa926eb5cecadda5c84f4 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Mon, 12 Aug 2019 19:11:06 +0200 Subject: [PATCH] parisc: Add ALTERNATIVE_CODE() and ALT_COND_RUN_ON_QEMU The macro ALTERNATIVE_CODE() allows assembly code to patch in a series of new assembler statements given at a specific start address. The ALT_COND_RUN_ON_QEMU condition is true if the kernel is started in a qemu emulation. Signed-off-by: Helge Deller --- arch/parisc/include/asm/alternative.h | 11 ++++++++++- arch/parisc/kernel/alternative.c | 23 +++++++++++++++++------ 2 files changed, 27 insertions(+), 7 deletions(-) diff --git a/arch/parisc/include/asm/alternative.h b/arch/parisc/include/asm/alternative.h index 793d8baa3a10..0ec54f43d6d2 100644 --- a/arch/parisc/include/asm/alternative.h +++ b/arch/parisc/include/asm/alternative.h @@ -8,6 +8,7 @@ #define ALT_COND_NO_ICACHE 0x04 /* if system has no i-cache */ #define ALT_COND_NO_SPLIT_TLB 0x08 /* if split_tlb == 0 */ #define ALT_COND_NO_IOC_FDC 0x10 /* if I/O cache does not need flushes */ +#define ALT_COND_RUN_ON_QEMU 0x20 /* if running on QEMU */ #define INSN_PxTLB 0x02 /* modify pdtlb, pitlb */ #define INSN_NOP 0x08000240 /* nop */ @@ -21,7 +22,7 @@ struct alt_instr { s32 orig_offset; /* offset to original instructions */ - u32 len; /* end of original instructions */ + s32 len; /* end of original instructions */ u32 cond; /* see ALT_COND_XXX */ u32 replacement; /* replacement instruction or code */ }; @@ -40,12 +41,20 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end, #else +/* to replace one single instructions by a new instruction */ #define ALTERNATIVE(from, to, cond, replacement)\ .section .altinstructions, "aw" ! \ .word (from - .), (to - from)/4 ! \ .word cond, replacement ! \ .previous +/* to replace multiple instructions by new code */ +#define ALTERNATIVE_CODE(from, num_instructions, cond, new_instr_ptr)\ + .section .altinstructions, "aw" ! \ + .word (from - .), -num_instructions ! \ + .word cond, (new_instr_ptr - .) ! \ + .previous + #endif /* __ASSEMBLY__ */ #endif /* __ASM_PARISC_ALTERNATIVE_H */ diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c index ca1f5ca0540a..3c66d5c4d90d 100644 --- a/arch/parisc/kernel/alternative.c +++ b/arch/parisc/kernel/alternative.c @@ -28,7 +28,8 @@ void __init_or_module apply_alternatives(struct alt_instr *start, for (entry = start; entry < end; entry++, index++) { - u32 *from, len, cond, replacement; + u32 *from, cond, replacement; + s32 len; from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset); len = entry->len; @@ -49,6 +50,8 @@ void __init_or_module apply_alternatives(struct alt_instr *start, continue; if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0)) continue; + if ((cond & ALT_COND_RUN_ON_QEMU) && !running_on_qemu) + continue; /* * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit @@ -74,11 +77,19 @@ void __init_or_module apply_alternatives(struct alt_instr *start, 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; + pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n", + index, cond, len, replacement, from, from); + + if (len < 0) { + /* Replace multiple instruction by new code */ + u32 *source; + len = -len; + source = (u32 *)((ulong)&entry->replacement + entry->replacement); + memcpy(from, source, 4 * len); + } else { + /* Replace by one instruction */ + *from = replacement; + } applied++; } -- 2.30.2