diff options
Diffstat (limited to 'arch/x86/kernel/paravirt.c')
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 60 |
1 files changed, 24 insertions, 36 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 7bbaa6baf37f..98039d7fb998 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -1,19 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* Paravirtualization interfaces Copyright (C) 2006 Rusty Russell IBM Corporation - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc */ @@ -70,24 +58,24 @@ struct branch { u32 delta; } __attribute__((packed)); -static unsigned paravirt_patch_call(void *insnbuf, const void *target, +static unsigned paravirt_patch_call(void *insn_buff, const void *target, unsigned long addr, unsigned len) { - struct branch *b = insnbuf; - unsigned long delta = (unsigned long)target - (addr+5); - - if (len < 5) { -#ifdef CONFIG_RETPOLINE - WARN_ONCE(1, "Failing to patch indirect CALL in %ps\n", (void *)addr); -#endif - return len; /* call too long for patch site */ + const int call_len = 5; + struct branch *b = insn_buff; + unsigned long delta = (unsigned long)target - (addr+call_len); + + if (len < call_len) { + pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr); + /* Kernel might not be viable if patching fails, bail out: */ + BUG_ON(1); } b->opcode = 0xe8; /* call */ b->delta = delta; - BUILD_BUG_ON(sizeof(*b) != 5); + BUILD_BUG_ON(sizeof(*b) != call_len); - return 5; + return call_len; } #ifdef CONFIG_PARAVIRT_XXL @@ -97,10 +85,10 @@ u64 notrace _paravirt_ident_64(u64 x) return x; } -static unsigned paravirt_patch_jmp(void *insnbuf, const void *target, +static unsigned paravirt_patch_jmp(void *insn_buff, const void *target, unsigned long addr, unsigned len) { - struct branch *b = insnbuf; + struct branch *b = insn_buff; unsigned long delta = (unsigned long)target - (addr+5); if (len < 5) { @@ -125,7 +113,7 @@ void __init native_pv_lock_init(void) static_branch_disable(&virt_spin_lock_key); } -unsigned paravirt_patch_default(u8 type, void *insnbuf, +unsigned paravirt_patch_default(u8 type, void *insn_buff, unsigned long addr, unsigned len) { /* @@ -137,36 +125,36 @@ unsigned paravirt_patch_default(u8 type, void *insnbuf, if (opfunc == NULL) /* If there's no function, patch it with a ud2a (BUG) */ - ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); + ret = paravirt_patch_insns(insn_buff, len, ud2a, ud2a+sizeof(ud2a)); else if (opfunc == _paravirt_nop) ret = 0; #ifdef CONFIG_PARAVIRT_XXL /* identity functions just return their single argument */ else if (opfunc == _paravirt_ident_64) - ret = paravirt_patch_ident_64(insnbuf, len); + ret = paravirt_patch_ident_64(insn_buff, len); else if (type == PARAVIRT_PATCH(cpu.iret) || type == PARAVIRT_PATCH(cpu.usergs_sysret64)) /* If operation requires a jmp, then jmp */ - ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); + ret = paravirt_patch_jmp(insn_buff, opfunc, addr, len); #endif else /* Otherwise call the function. */ - ret = paravirt_patch_call(insnbuf, opfunc, addr, len); + ret = paravirt_patch_call(insn_buff, opfunc, addr, len); return ret; } -unsigned paravirt_patch_insns(void *insnbuf, unsigned len, +unsigned paravirt_patch_insns(void *insn_buff, unsigned len, const char *start, const char *end) { unsigned insn_len = end - start; - if (insn_len > len || start == NULL) - insn_len = len; - else - memcpy(insnbuf, start, insn_len); + /* Alternative instruction is too large for the patch site and we cannot continue: */ + BUG_ON(insn_len > len || start == NULL); + + memcpy(insn_buff, start, insn_len); return insn_len; } |