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Commit 92ff0674 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: mm: Rework unhandled user pagefaults to call arm64_force_sig_info 



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: default avatarWill Deacon <will.deacon@arm.com>
parent 1049c308

arch/arm64/mm/fault.c

+36 −51
Original line number Diff line number Diff line
@@ -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>
@@ -289,59 +290,32 @@ 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

#define VM_FAULT_BADACCESS	0x020000
@@ -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 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
		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 ?

		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;



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