The following commit has been merged into the x86/mm branch of tip: Commit-ID: ec352711ceba890ea3a0c182c2d49c86c1a5e30e Gitweb: https://git.kernel.org/tip/ec352711ceba890ea3a0c182c2d49c86c1a5e30e Author: Andy Lutomirski <l...@kernel.org> AuthorDate: Tue, 09 Feb 2021 18:33:35 -08:00 Committer: Borislav Petkov <b...@suse.de> CommitterDate: Wed, 10 Feb 2021 14:10:07 +01:00
x86/fault: Fold mm_fault_error() into do_user_addr_fault() mm_fault_error() is logically just the end of do_user_addr_fault(). Combine the functions. This makes the code easier to read. Most of the churn here is from renaming hw_error_code to error_code in do_user_addr_fault(). This makes no difference at all to the generated code (objdump -dr) as compared to changing noinline to __always_inline in the definition of mm_fault_error(). Signed-off-by: Andy Lutomirski <l...@kernel.org> Signed-off-by: Borislav Petkov <b...@suse.de> Link: https://lkml.kernel.org/r/dedc4d9c9b047e51ce38b991bd23971a28af4e7b.1612924255.git.l...@kernel.org --- arch/x86/mm/fault.c | 97 ++++++++++++++++++++------------------------ 1 file changed, 45 insertions(+), 52 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 818902b..91cf7a6 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -981,40 +981,6 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address); } -static noinline void -mm_fault_error(struct pt_regs *regs, unsigned long error_code, - unsigned long address, vm_fault_t fault) -{ - if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) { - no_context(regs, error_code, address, 0, 0); - return; - } - - if (fault & VM_FAULT_OOM) { - /* Kernel mode? Handle exceptions or die: */ - if (!(error_code & X86_PF_USER)) { - no_context(regs, error_code, address, - SIGSEGV, SEGV_MAPERR); - return; - } - - /* - * We ran out of memory, call the OOM killer, and return the - * userspace (which will retry the fault, or kill us if we got - * oom-killed): - */ - pagefault_out_of_memory(); - } else { - if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON| - VM_FAULT_HWPOISON_LARGE)) - do_sigbus(regs, error_code, address, fault); - else if (fault & VM_FAULT_SIGSEGV) - bad_area_nosemaphore(regs, error_code, address); - else - BUG(); - } -} - static int spurious_kernel_fault_check(unsigned long error_code, pte_t *pte) { if ((error_code & X86_PF_WRITE) && !pte_write(*pte)) @@ -1252,7 +1218,7 @@ NOKPROBE_SYMBOL(do_kern_addr_fault); /* Handle faults in the user portion of the address space */ static inline void do_user_addr_fault(struct pt_regs *regs, - unsigned long hw_error_code, + unsigned long error_code, unsigned long address) { struct vm_area_struct *vma; @@ -1272,8 +1238,8 @@ void do_user_addr_fault(struct pt_regs *regs, * Reserved bits are never expected to be set on * entries in the user portion of the page tables. */ - if (unlikely(hw_error_code & X86_PF_RSVD)) - pgtable_bad(regs, hw_error_code, address); + if (unlikely(error_code & X86_PF_RSVD)) + pgtable_bad(regs, error_code, address); /* * If SMAP is on, check for invalid kernel (supervisor) access to user @@ -1283,10 +1249,10 @@ void do_user_addr_fault(struct pt_regs *regs, * enforcement appears to be consistent with the USER bit. */ if (unlikely(cpu_feature_enabled(X86_FEATURE_SMAP) && - !(hw_error_code & X86_PF_USER) && + !(error_code & X86_PF_USER) && !(regs->flags & X86_EFLAGS_AC))) { - bad_area_nosemaphore(regs, hw_error_code, address); + bad_area_nosemaphore(regs, error_code, address); return; } @@ -1295,7 +1261,7 @@ void do_user_addr_fault(struct pt_regs *regs, * in a region with pagefaults disabled then we must not take the fault */ if (unlikely(faulthandler_disabled() || !mm)) { - bad_area_nosemaphore(regs, hw_error_code, address); + bad_area_nosemaphore(regs, error_code, address); return; } @@ -1316,9 +1282,9 @@ void do_user_addr_fault(struct pt_regs *regs, perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); - if (hw_error_code & X86_PF_WRITE) + if (error_code & X86_PF_WRITE) flags |= FAULT_FLAG_WRITE; - if (hw_error_code & X86_PF_INSTR) + if (error_code & X86_PF_INSTR) flags |= FAULT_FLAG_INSTRUCTION; #ifdef CONFIG_X86_64 @@ -1334,7 +1300,7 @@ void do_user_addr_fault(struct pt_regs *regs, * to consider the PF_PK bit. */ if (is_vsyscall_vaddr(address)) { - if (emulate_vsyscall(hw_error_code, regs, address)) + if (emulate_vsyscall(error_code, regs, address)) return; } #endif @@ -1357,7 +1323,7 @@ void do_user_addr_fault(struct pt_regs *regs, * Fault from code in kernel from * which we do not expect faults. */ - bad_area_nosemaphore(regs, hw_error_code, address); + bad_area_nosemaphore(regs, error_code, address); return; } retry: @@ -1373,17 +1339,17 @@ retry: vma = find_vma(mm, address); if (unlikely(!vma)) { - bad_area(regs, hw_error_code, address); + bad_area(regs, error_code, address); return; } if (likely(vma->vm_start <= address)) goto good_area; if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) { - bad_area(regs, hw_error_code, address); + bad_area(regs, error_code, address); return; } if (unlikely(expand_stack(vma, address))) { - bad_area(regs, hw_error_code, address); + bad_area(regs, error_code, address); return; } @@ -1392,8 +1358,8 @@ retry: * we can handle it.. */ good_area: - if (unlikely(access_error(hw_error_code, vma))) { - bad_area_access_error(regs, hw_error_code, address, vma); + if (unlikely(access_error(error_code, vma))) { + bad_area_access_error(regs, error_code, address, vma); return; } @@ -1415,7 +1381,7 @@ good_area: /* Quick path to respond to signals */ if (fault_signal_pending(fault, regs)) { if (!user_mode(regs)) - no_context(regs, hw_error_code, address, SIGBUS, + no_context(regs, error_code, address, SIGBUS, BUS_ADRERR); return; } @@ -1432,11 +1398,38 @@ good_area: } mmap_read_unlock(mm); - if (unlikely(fault & VM_FAULT_ERROR)) { - mm_fault_error(regs, hw_error_code, address, fault); + if (likely(!(fault & VM_FAULT_ERROR))) + return; + + if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) { + no_context(regs, error_code, address, 0, 0); return; } + if (fault & VM_FAULT_OOM) { + /* Kernel mode? Handle exceptions or die: */ + if (!(error_code & X86_PF_USER)) { + no_context(regs, error_code, address, + SIGSEGV, SEGV_MAPERR); + return; + } + + /* + * We ran out of memory, call the OOM killer, and return the + * userspace (which will retry the fault, or kill us if we got + * oom-killed): + */ + pagefault_out_of_memory(); + } else { + if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON| + VM_FAULT_HWPOISON_LARGE)) + do_sigbus(regs, error_code, address, fault); + else if (fault & VM_FAULT_SIGSEGV) + bad_area_nosemaphore(regs, error_code, address); + else + BUG(); + } + check_v8086_mode(regs, address, tsk); } NOKPROBE_SYMBOL(do_user_addr_fault);