Message ID | 1504910713-7094-31-git-send-email-linuxram@us.ibm.com (mailing list archive) |
---|---|
State | Changes Requested |
Headers | show |
Series | powerpc: Free up RPAGE_RSV bits | expand |
Ram Pai <linuxram@us.ibm.com> writes: > diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h > index 04b60af..51c89c1 100644 > --- a/arch/powerpc/include/asm/paca.h > +++ b/arch/powerpc/include/asm/paca.h > @@ -97,6 +97,9 @@ struct paca_struct { > struct dtl_entry *dispatch_log_end; > #endif /* CONFIG_PPC_STD_MMU_64 */ > u64 dscr_default; /* per-CPU default DSCR */ > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > + u16 paca_pkey; /* exception causing pkey */ > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ I can't see any reason why this should be in the paca. > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index a16bc43..ad31f6e 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -153,6 +153,7 @@ static int bad_page_fault_exception(struct pt_regs *regs, unsigned long address, > > #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > if (si_code & DSISR_KEYFAULT) { > + get_paca()->paca_pkey = get_pte_pkey(current->mm, address); You seem to be using the paca as a temporary stash so that you don't have to pass it to _exception(). But that's not what the paca is for, the paca is for per-cpu data not per-thread data, and (preferably) only for things that need to be accessed in low-level code where proper per_cpu() variables don't work. Updating _exception() to take the key would be a mess, because there are so many callers who don't care about the key. For now we can probably just do something ~=: void _exception_pkey(int signr, struct pt_regs *regs, int code, unsigned long addr, int key) { < current body of _exception > + pkey bits } void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) { _exception_pkey(..., 0); } cheers
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 04b60af..51c89c1 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -97,6 +97,9 @@ struct paca_struct { struct dtl_entry *dispatch_log_end; #endif /* CONFIG_PPC_STD_MMU_64 */ u64 dscr_default; /* per-CPU default DSCR */ +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + u16 paca_pkey; /* exception causing pkey */ +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ #ifdef CONFIG_PPC_STD_MMU_64 /* diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 8cfb20e..361f0d4 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -241,6 +241,11 @@ int main(void) OFFSET(PACAHWCPUID, paca_struct, hw_cpu_id); OFFSET(PACAKEXECSTATE, paca_struct, kexec_state); OFFSET(PACA_DSCR_DEFAULT, paca_struct, dscr_default); + +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + OFFSET(PACA_PKEY, paca_struct, paca_pkey); +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ + OFFSET(ACCOUNT_STARTTIME, paca_struct, accounting.starttime); OFFSET(ACCOUNT_STARTTIME_USER, paca_struct, accounting.starttime_user); OFFSET(ACCOUNT_USER_TIME, paca_struct, accounting.utime); diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index a16bc43..ad31f6e 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -153,6 +153,7 @@ static int bad_page_fault_exception(struct pt_regs *regs, unsigned long address, #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS if (si_code & DSISR_KEYFAULT) { + get_paca()->paca_pkey = get_pte_pkey(current->mm, address); sig = SIGSEGV; code = SEGV_PKUERR; } @@ -509,8 +510,16 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, - is_exec, 0)) + is_exec, 0)) { + /* + * The pgd-pdt...pmd-pte tree may not have been fully setup. + * Hence we cannot walk the tree to locate the pte, to locate + * the key. Hence lets use vma_pkey() to get the key; instead + * of get_pte_pkey(). + */ + get_paca()->paca_pkey = vma_pkey(vma); return __bad_area(regs, address, SEGV_PKUERR); + } #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
Capture the protection key that got violated in paca. This value will be later used to inform the signal handler. Signed-off-by: Ram Pai <linuxram@us.ibm.com> --- arch/powerpc/include/asm/paca.h | 3 +++ arch/powerpc/kernel/asm-offsets.c | 5 +++++ arch/powerpc/mm/fault.c | 11 ++++++++++- 3 files changed, 18 insertions(+), 1 deletions(-)