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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 <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/dedc4d9c9b047e51ce38b991bd23971a28af4e7b.1612924255.git.luto@kernel.org
This commit is contained in:
Andy Lutomirski
Borislav Petkov
parent
d24df8ecf9
commit
ec352711ce
1 changed files with 45 additions and 52 deletions
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@ -981,40 +981,6 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
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force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
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}
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static noinline void
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mm_fault_error(struct pt_regs *regs, unsigned long error_code,
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unsigned long address, vm_fault_t fault)
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{
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if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
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no_context(regs, error_code, address, 0, 0);
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return;
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}
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if (fault & VM_FAULT_OOM) {
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/* Kernel mode? Handle exceptions or die: */
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if (!(error_code & X86_PF_USER)) {
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no_context(regs, error_code, address,
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SIGSEGV, SEGV_MAPERR);
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return;
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}
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/*
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* We ran out of memory, call the OOM killer, and return the
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* userspace (which will retry the fault, or kill us if we got
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* oom-killed):
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*/
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pagefault_out_of_memory();
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} else {
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if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
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VM_FAULT_HWPOISON_LARGE))
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do_sigbus(regs, error_code, address, fault);
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else if (fault & VM_FAULT_SIGSEGV)
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bad_area_nosemaphore(regs, error_code, address);
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else
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BUG();
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}
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}
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static int spurious_kernel_fault_check(unsigned long error_code, pte_t *pte)
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{
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if ((error_code & X86_PF_WRITE) && !pte_write(*pte))
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@ -1252,7 +1218,7 @@ NOKPROBE_SYMBOL(do_kern_addr_fault);
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/* Handle faults in the user portion of the address space */
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static inline
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void do_user_addr_fault(struct pt_regs *regs,
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unsigned long hw_error_code,
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unsigned long error_code,
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unsigned long address)
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{
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struct vm_area_struct *vma;
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@ -1272,8 +1238,8 @@ void do_user_addr_fault(struct pt_regs *regs,
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* Reserved bits are never expected to be set on
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* entries in the user portion of the page tables.
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*/
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if (unlikely(hw_error_code & X86_PF_RSVD))
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pgtable_bad(regs, hw_error_code, address);
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if (unlikely(error_code & X86_PF_RSVD))
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pgtable_bad(regs, error_code, address);
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/*
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* If SMAP is on, check for invalid kernel (supervisor) access to user
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@ -1283,10 +1249,10 @@ void do_user_addr_fault(struct pt_regs *regs,
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* enforcement appears to be consistent with the USER bit.
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*/
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if (unlikely(cpu_feature_enabled(X86_FEATURE_SMAP) &&
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!(hw_error_code & X86_PF_USER) &&
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!(error_code & X86_PF_USER) &&
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!(regs->flags & X86_EFLAGS_AC)))
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{
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bad_area_nosemaphore(regs, hw_error_code, address);
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bad_area_nosemaphore(regs, error_code, address);
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return;
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}
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@ -1295,7 +1261,7 @@ void do_user_addr_fault(struct pt_regs *regs,
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* in a region with pagefaults disabled then we must not take the fault
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*/
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if (unlikely(faulthandler_disabled() || !mm)) {
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bad_area_nosemaphore(regs, hw_error_code, address);
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bad_area_nosemaphore(regs, error_code, address);
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return;
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}
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@ -1316,9 +1282,9 @@ void do_user_addr_fault(struct pt_regs *regs,
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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if (hw_error_code & X86_PF_WRITE)
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if (error_code & X86_PF_WRITE)
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flags |= FAULT_FLAG_WRITE;
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if (hw_error_code & X86_PF_INSTR)
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if (error_code & X86_PF_INSTR)
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flags |= FAULT_FLAG_INSTRUCTION;
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#ifdef CONFIG_X86_64
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@ -1334,7 +1300,7 @@ void do_user_addr_fault(struct pt_regs *regs,
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* to consider the PF_PK bit.
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*/
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if (is_vsyscall_vaddr(address)) {
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if (emulate_vsyscall(hw_error_code, regs, address))
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if (emulate_vsyscall(error_code, regs, address))
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return;
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}
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#endif
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@ -1357,7 +1323,7 @@ void do_user_addr_fault(struct pt_regs *regs,
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* Fault from code in kernel from
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* which we do not expect faults.
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*/
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bad_area_nosemaphore(regs, hw_error_code, address);
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bad_area_nosemaphore(regs, error_code, address);
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return;
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}
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retry:
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@ -1373,17 +1339,17 @@ void do_user_addr_fault(struct pt_regs *regs,
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vma = find_vma(mm, address);
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if (unlikely(!vma)) {
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bad_area(regs, hw_error_code, address);
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bad_area(regs, error_code, address);
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return;
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}
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if (likely(vma->vm_start <= address))
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goto good_area;
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if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
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bad_area(regs, hw_error_code, address);
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bad_area(regs, error_code, address);
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return;
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}
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if (unlikely(expand_stack(vma, address))) {
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bad_area(regs, hw_error_code, address);
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bad_area(regs, error_code, address);
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return;
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}
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@ -1392,8 +1358,8 @@ void do_user_addr_fault(struct pt_regs *regs,
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* we can handle it..
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*/
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good_area:
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if (unlikely(access_error(hw_error_code, vma))) {
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bad_area_access_error(regs, hw_error_code, address, vma);
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if (unlikely(access_error(error_code, vma))) {
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bad_area_access_error(regs, error_code, address, vma);
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return;
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}
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@ -1415,7 +1381,7 @@ void do_user_addr_fault(struct pt_regs *regs,
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/* Quick path to respond to signals */
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if (fault_signal_pending(fault, regs)) {
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if (!user_mode(regs))
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no_context(regs, hw_error_code, address, SIGBUS,
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no_context(regs, error_code, address, SIGBUS,
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BUS_ADRERR);
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return;
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}
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@ -1432,9 +1398,36 @@ void do_user_addr_fault(struct pt_regs *regs,
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}
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mmap_read_unlock(mm);
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if (unlikely(fault & VM_FAULT_ERROR)) {
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mm_fault_error(regs, hw_error_code, address, fault);
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if (likely(!(fault & VM_FAULT_ERROR)))
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return;
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if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
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no_context(regs, error_code, address, 0, 0);
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return;
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}
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if (fault & VM_FAULT_OOM) {
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/* Kernel mode? Handle exceptions or die: */
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if (!(error_code & X86_PF_USER)) {
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no_context(regs, error_code, address,
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SIGSEGV, SEGV_MAPERR);
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return;
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}
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/*
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* We ran out of memory, call the OOM killer, and return the
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* userspace (which will retry the fault, or kill us if we got
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* oom-killed):
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*/
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pagefault_out_of_memory();
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} else {
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if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
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VM_FAULT_HWPOISON_LARGE))
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do_sigbus(regs, error_code, address, fault);
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else if (fault & VM_FAULT_SIGSEGV)
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bad_area_nosemaphore(regs, error_code, address);
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else
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BUG();
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}
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check_v8086_mode(regs, address, tsk);
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