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riscv/mm/fault: Move no context handling to no_context()

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This patch moves the no context handling in do_page_fault() to
no_context() function and converts gotos to calls to the new function.

Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Pekka Enberg 2020-08-25 18:38:58 +03:00 committed by Palmer Dabbelt
parent 4363287178
commit cac4d1dc85
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 52 additions and 31 deletions
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83
arch/riscv/mm/fault.c
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@ -19,6 +19,24 @@
#include "../kernel/head.h"
static inline void no_context(struct pt_regs *regs, unsigned long addr)
{
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
pr_alert("Unable to handle kernel %s at virtual address " REG_FMT "\n",
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
"paging request", addr);
die(regs, "Oops");
do_exit(SIGKILL);
}
/*
* This routine handles page faults. It determines the address and the
* problem, and then passes it off to one of the appropriate routines.
@ -59,8 +77,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
* If we're in an interrupt, have no user context, or are running
* in an atomic region, then we must not take the fault.
*/
if (unlikely(faulthandler_disabled() || !mm))
goto no_context;
if (unlikely(faulthandler_disabled() || !mm)) {
no_context(regs, addr);
return;
}
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
@ -153,21 +173,8 @@ bad_area:
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
pr_alert("Unable to handle kernel %s at virtual address " REG_FMT "\n",
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
"paging request", addr);
die(regs, "Oops");
do_exit(SIGKILL);
no_context(regs, addr);
return;
/*
* We ran out of memory, call the OOM killer, and return the userspace
@ -175,16 +182,20 @@ no_context:
*/
out_of_memory:
mmap_read_unlock(mm);
if (!user_mode(regs))
goto no_context;
if (!user_mode(regs)) {
no_context(regs, addr);
return;
}
pagefault_out_of_memory();
return;
do_sigbus:
mmap_read_unlock(mm);
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
goto no_context;
if (!user_mode(regs)) {
no_context(regs, addr);
return;
}
do_trap(regs, SIGBUS, BUS_ADRERR, addr);
return;
@ -213,19 +224,25 @@ vmalloc_fault:
pgd = (pgd_t *)pfn_to_virt(csr_read(CSR_SATP)) + index;
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))
goto no_context;
if (!pgd_present(*pgd_k)) {
no_context(regs, addr);
return;
}
set_pgd(pgd, *pgd_k);
p4d = p4d_offset(pgd, addr);
p4d_k = p4d_offset(pgd_k, addr);
if (!p4d_present(*p4d_k))
goto no_context;
if (!p4d_present(*p4d_k)) {
no_context(regs, addr);
return;
}
pud = pud_offset(p4d, addr);
pud_k = pud_offset(p4d_k, addr);
if (!pud_present(*pud_k))
goto no_context;
if (!pud_present(*pud_k)) {
no_context(regs, addr);
return;
}
/*
* Since the vmalloc area is global, it is unnecessary
@ -233,8 +250,10 @@ vmalloc_fault:
*/
pmd = pmd_offset(pud, addr);
pmd_k = pmd_offset(pud_k, addr);
if (!pmd_present(*pmd_k))
goto no_context;
if (!pmd_present(*pmd_k)) {
no_context(regs, addr);
return;
}
set_pmd(pmd, *pmd_k);
/*
@ -244,8 +263,10 @@ vmalloc_fault:
* silently loop forever.
*/
pte_k = pte_offset_kernel(pmd_k, addr);
if (!pte_present(*pte_k))
goto no_context;
if (!pte_present(*pte_k)) {
no_context(regs, addr);
return;
}
/*
* The kernel assumes that TLBs don't cache invalid