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arm64: mm: Rework unhandled user pagefaults to call arm64_force_sig_info

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Reporting unhandled user pagefaults via arm64_force_sig_info means
that __do_user_fault can be drastically simplified, since it no longer
has to worry about printing the fault information and can consequently
just take the siginfo as a parameter.

Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2018-02-20 14:53:22 +00:00
parent 1049c30871
commit 92ff0674f5
1 changed files with 36 additions and 51 deletions
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87
arch/arm64/mm/fault.c
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@ -43,6 +43,7 @@
#include <asm/system_misc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>
#include <acpi/ghes.h>
@ -289,58 +290,31 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
do_exit(SIGKILL);
}
static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
unsigned int esr, unsigned int sig, int code,
struct pt_regs *regs, int fault)
static void __do_user_fault(struct siginfo *info, unsigned int esr)
{
struct siginfo si;
const struct fault_info *inf;
unsigned int lsb = 0;
if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) {
inf = esr_to_fault_info(esr);
pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x",
tsk->comm, task_pid_nr(tsk), inf->name, sig,
addr, esr);
print_vma_addr(KERN_CONT ", in ", regs->pc);
pr_cont("\n");
__show_regs(regs);
}
tsk->thread.fault_address = addr;
tsk->thread.fault_code = esr;
si.si_signo = sig;
si.si_errno = 0;
si.si_code = code;
si.si_addr = (void __user *)addr;
/*
* Either small page or large page may be poisoned.
* In other words, VM_FAULT_HWPOISON_LARGE and
* VM_FAULT_HWPOISON are mutually exclusive.
*/
if (fault & VM_FAULT_HWPOISON_LARGE)
lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
else if (fault & VM_FAULT_HWPOISON)
lsb = PAGE_SHIFT;
si.si_addr_lsb = lsb;
force_sig_info(sig, &si, tsk);
current->thread.fault_address = (unsigned long)info->si_addr;
current->thread.fault_code = esr;
arm64_force_sig_info(info, esr_to_fault_info(esr)->name, current);
}
static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
{
struct task_struct *tsk = current;
const struct fault_info *inf;
/*
* If we are in kernel mode at this point, we have no context to
* handle this fault with.
*/
if (user_mode(regs)) {
inf = esr_to_fault_info(esr);
__do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs, 0);
} else
const struct fault_info *inf = esr_to_fault_info(esr);
struct siginfo si = {
.si_signo = inf->sig,
.si_code = inf->code,
.si_addr = (void __user *)addr,
};
__do_user_fault(&si, esr);
} else {
__do_kernel_fault(addr, esr, regs);
}
}
#define VM_FAULT_BADMAP 0x010000
@ -393,7 +367,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
{
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code, major = 0;
struct siginfo si;
int fault, major = 0;
unsigned long vm_flags = VM_READ | VM_WRITE;
unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
@ -525,27 +500,37 @@ retry:
return 0;
}
clear_siginfo(&si);
si.si_addr = (void __user *)addr;
if (fault & VM_FAULT_SIGBUS) {
/*
* We had some memory, but were unable to successfully fix up
* this page fault.
*/
sig = SIGBUS;
code = BUS_ADRERR;
} else if (fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) {
sig = SIGBUS;
code = BUS_MCEERR_AR;
si.si_signo = SIGBUS;
si.si_code = BUS_ADRERR;
} else if (fault & VM_FAULT_HWPOISON_LARGE) {
unsigned int hindex = VM_FAULT_GET_HINDEX(fault);
si.si_signo = SIGBUS;
si.si_code = BUS_MCEERR_AR;
si.si_addr_lsb = hstate_index_to_shift(hindex);
} else if (fault & VM_FAULT_HWPOISON) {
si.si_signo = SIGBUS;
si.si_code = BUS_MCEERR_AR;
si.si_addr_lsb = PAGE_SHIFT;
} else {
/*
* Something tried to access memory that isn't in our memory
* map.
*/
sig = SIGSEGV;
code = fault == VM_FAULT_BADACCESS ?
SEGV_ACCERR : SEGV_MAPERR;
si.si_signo = SIGSEGV;
si.si_code = fault == VM_FAULT_BADACCESS ?
SEGV_ACCERR : SEGV_MAPERR;
}
__do_user_fault(tsk, addr, esr, sig, code, regs, fault);
__do_user_fault(&si, esr);
return 0;
no_context: