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Message-Id: <20231210062138.2417-6-jgross@suse.com> Date: Sun, 10 Dec 2023 07:21:38 +0100 From: Juergen Gross <jgross@...e.com> To: linux-kernel@...r.kernel.org, x86@...nel.org, virtualization@...ts.linux.dev Cc: Juergen Gross <jgross@...e.com>, Ajay Kaher <akaher@...are.com>, Alexey Makhalov <amakhalov@...are.com>, VMware PV-Drivers Reviewers <pv-drivers@...are.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, "H. Peter Anvin" <hpa@...or.com>, Peter Zijlstra <peterz@...radead.org> Subject: [PATCH v6 5/5] x86/paravirt: remove no longer needed paravirt patching code Now that paravirt is using the alternatives patching infrastructure, remove the paravirt patching code. Signed-off-by: Juergen Gross <jgross@...e.com> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org> --- arch/x86/include/asm/paravirt.h | 13 ------ arch/x86/include/asm/paravirt_types.h | 38 --------------- arch/x86/include/asm/text-patching.h | 12 ----- arch/x86/kernel/alternative.c | 67 +-------------------------- arch/x86/kernel/paravirt.c | 30 ------------ arch/x86/kernel/vmlinux.lds.S | 13 ------ arch/x86/tools/relocs.c | 2 +- 7 files changed, 3 insertions(+), 172 deletions(-) diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 973c2ac2d25c..8bcf7584e7dd 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -725,23 +725,10 @@ void native_pv_lock_init(void) __init; #else /* __ASSEMBLY__ */ -#define _PVSITE(ptype, ops) \ -771:; \ - ops; \ -772:; \ - .pushsection .parainstructions,"a"; \ - .long 771b-.; \ - .byte ptype; \ - .byte 772b-771b; \ - .popsection - - #ifdef CONFIG_X86_64 #ifdef CONFIG_PARAVIRT_XXL #ifdef CONFIG_DEBUG_ENTRY -#define PARA_PATCH(off) ((off) / 8) -#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops) #define PARA_INDIRECT(addr) *addr(%rip) .macro PARA_IRQ_save_fl diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 9cad536fc08d..d8e85d2cf8d5 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -2,15 +2,6 @@ #ifndef _ASM_X86_PARAVIRT_TYPES_H #define _ASM_X86_PARAVIRT_TYPES_H -#ifndef __ASSEMBLY__ -/* These all sit in the .parainstructions section to tell us what to patch. */ -struct paravirt_patch_site { - s32 instr_offset; /* original instructions */ - u8 type; /* type of this instruction */ - u8 len; /* length of original instruction */ -} __packed; -#endif - #ifdef CONFIG_PARAVIRT #ifndef __ASSEMBLY__ @@ -250,32 +241,6 @@ struct paravirt_patch_template { extern struct pv_info pv_info; extern struct paravirt_patch_template pv_ops; -#define PARAVIRT_PATCH(x) \ - (offsetof(struct paravirt_patch_template, x) / sizeof(void *)) - -#define paravirt_type(op) \ - [paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \ - [paravirt_opptr] "m" (pv_ops.op) -/* - * Generate some code, and mark it as patchable by the - * apply_paravirt() alternate instruction patcher. - */ -#define _paravirt_alt(insn_string, type) \ - "771:\n\t" insn_string "\n" "772:\n" \ - ".pushsection .parainstructions,\"a\"\n" \ - " .long 771b-.\n" \ - " .byte " type "\n" \ - " .byte 772b-771b\n" \ - ".popsection\n" - -/* Generate patchable code, with the default asm parameters. */ -#define paravirt_alt(insn_string) \ - _paravirt_alt(insn_string, "%c[paravirt_typenum]") - -/* Simple instruction patching code. */ -#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t" - -unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, unsigned int len); #define paravirt_ptr(op) [paravirt_opptr] "m" (pv_ops.op) int paravirt_disable_iospace(void); @@ -555,9 +520,6 @@ unsigned long pv_native_read_cr2(void); #define paravirt_nop ((void *)nop_func) -extern struct paravirt_patch_site __parainstructions[], - __parainstructions_end[]; - #endif /* __ASSEMBLY__ */ #define ALT_NOT_XEN ALT_NOT(X86_FEATURE_XENPV) diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 29832c338cdc..0b70653a98c1 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -6,18 +6,6 @@ #include <linux/stddef.h> #include <asm/ptrace.h> -struct paravirt_patch_site; -#ifdef CONFIG_PARAVIRT -void apply_paravirt(struct paravirt_patch_site *start, - struct paravirt_patch_site *end); -#else -static inline void apply_paravirt(struct paravirt_patch_site *start, - struct paravirt_patch_site *end) -{} -#define __parainstructions NULL -#define __parainstructions_end NULL -#endif - /* * Currently, the max observed size in the kernel code is * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5. diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index ab829b3d028d..2cad05ff7656 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1472,48 +1472,6 @@ int alternatives_text_reserved(void *start, void *end) } #endif /* CONFIG_SMP */ -#ifdef CONFIG_PARAVIRT - -/* Use this to add nops to a buffer, then text_poke the whole buffer. */ -static void __init_or_module add_nops(void *insns, unsigned int len) -{ - while (len > 0) { - unsigned int noplen = len; - if (noplen > ASM_NOP_MAX) - noplen = ASM_NOP_MAX; - memcpy(insns, x86_nops[noplen], noplen); - insns += noplen; - len -= noplen; - } -} - -void __init_or_module apply_paravirt(struct paravirt_patch_site *start, - struct paravirt_patch_site *end) -{ - struct paravirt_patch_site *p; - char insn_buff[MAX_PATCH_LEN]; - u8 *instr; - - for (p = start; p < end; p++) { - unsigned int used; - - instr = (u8 *)&p->instr_offset + p->instr_offset; - BUG_ON(p->len > MAX_PATCH_LEN); - /* prep the buffer with the original instructions */ - memcpy(insn_buff, instr, p->len); - used = paravirt_patch(p->type, insn_buff, (unsigned long)instr, p->len); - - BUG_ON(used > p->len); - - /* Pad the rest with nops */ - add_nops(insn_buff + used, p->len - used); - text_poke_early(instr, insn_buff, p->len); - } -} -extern struct paravirt_patch_site __start_parainstructions[], - __stop_parainstructions[]; -#endif /* CONFIG_PARAVIRT */ - /* * Self-test for the INT3 based CALL emulation code. * @@ -1649,28 +1607,11 @@ void __init alternative_instructions(void) */ /* - * Paravirt patching and alternative patching can be combined to - * replace a function call with a short direct code sequence (e.g. - * by setting a constant return value instead of doing that in an - * external function). - * In order to make this work the following sequence is required: - * 1. set (artificial) features depending on used paravirt - * functions which can later influence alternative patching - * 2. apply paravirt patching (generally replacing an indirect - * function call with a direct one) - * 3. apply alternative patching (e.g. replacing a direct function - * call with a custom code sequence) - * Doing paravirt patching after alternative patching would clobber - * the optimization of the custom code with a function call again. + * Make sure to set (artificial) features depending on used paravirt + * functions which can later influence alternative patching. */ paravirt_set_cap(); - /* - * First patch paravirt functions, such that we overwrite the indirect - * call with the direct call. - */ - apply_paravirt(__parainstructions, __parainstructions_end); - __apply_fineibt(__retpoline_sites, __retpoline_sites_end, __cfi_sites, __cfi_sites_end, true); @@ -1681,10 +1622,6 @@ void __init alternative_instructions(void) apply_retpolines(__retpoline_sites, __retpoline_sites_end); apply_returns(__return_sites, __return_sites_end); - /* - * Then patch alternatives, such that those paravirt calls that are in - * alternatives can be overwritten by their immediate fragments. - */ apply_alternatives(__alt_instructions, __alt_instructions_end); /* diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index acc5b1004f0f..5358d43886ad 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -43,14 +43,6 @@ void __init default_banner(void) pv_info.name); } -static unsigned paravirt_patch_call(void *insn_buff, const void *target, - unsigned long addr, unsigned len) -{ - __text_gen_insn(insn_buff, CALL_INSN_OPCODE, - (void *)addr, target, CALL_INSN_SIZE); - return CALL_INSN_SIZE; -} - #ifdef CONFIG_PARAVIRT_XXL DEFINE_ASM_FUNC(_paravirt_ident_64, "mov %rdi, %rax", .text); DEFINE_ASM_FUNC(pv_native_save_fl, "pushf; pop %rax", .noinstr.text); @@ -73,28 +65,6 @@ static void native_tlb_remove_table(struct mmu_gather *tlb, void *table) tlb_remove_page(tlb, table); } -unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, - unsigned int len) -{ - /* - * Neat trick to map patch type back to the call within the - * corresponding structure. - */ - void *opfunc = *((void **)&pv_ops + type); - unsigned ret; - - if (opfunc == NULL) - /* If there's no function, patch it with BUG_func() */ - ret = paravirt_patch_call(insn_buff, BUG_func, addr, len); - else if (opfunc == nop_func) - ret = 0; - else - /* Otherwise call the function. */ - ret = paravirt_patch_call(insn_buff, opfunc, addr, len); - - return ret; -} - struct static_key paravirt_steal_enabled; struct static_key paravirt_steal_rq_enabled; diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 54a5596adaa6..a349dbfc6d5a 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -267,19 +267,6 @@ SECTIONS } #endif - /* - * start address and size of operations which during runtime - * can be patched with virtualization friendly instructions or - * baremetal native ones. Think page table operations. - * Details in paravirt_types.h - */ - . = ALIGN(8); - .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { - __parainstructions = .; - *(.parainstructions) - __parainstructions_end = .; - } - #ifdef CONFIG_RETPOLINE /* * List of instructions that call/jmp/jcc to retpoline thunks diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index d30949e25ebd..a3bae2b24626 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -66,7 +66,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = { [S_REL] = "^(__init_(begin|end)|" "__x86_cpu_dev_(start|end)|" - "(__parainstructions|__alt_instructions)(_end)?|" + "__alt_instructions(_end)?|" "(__iommu_table|__apicdrivers|__smp_locks)(_end)?|" "__(start|end)_pci_.*|" #if CONFIG_FW_LOADER -- 2.35.3
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