| Message ID | 20220127100622.11856-1-hanchuanhua@oppo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: mm: Remove the copy operation of pmd | expand |
On Thu, 27 Jan 2022 02:06:22 PST (-0800), hanchuanhua@oppo.com wrote: > Since all processes share the kernel address space, > we only need to copy pgd in case of a vmalloc page > fault exception, the other levels of page tables are > shared, so the operation of copying pmd is unnecessary. > > Signed-off-by: hanchuanhua <hanchuanhua@oppo.com> > --- > arch/riscv/mm/fault.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c > index 4e9efbe..40694f0 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code > static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr) > { > pgd_t *pgd, *pgd_k; > - pud_t *pud, *pud_k; > - p4d_t *p4d, *p4d_k; > - pmd_t *pmd, *pmd_k; > + pud_t *pud_k; > + p4d_t *p4d_k; > + pmd_t *pmd_k; > pte_t *pte_k; > int index; > unsigned long pfn; > @@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a > } > set_pgd(pgd, *pgd_k); > > - p4d = p4d_offset(pgd, addr); > p4d_k = p4d_offset(pgd_k, addr); > 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)) { > no_context(regs, addr); > @@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a > * Since the vmalloc area is global, it is unnecessary > * to copy individual PTEs > */ > - pmd = pmd_offset(pud, addr); > pmd_k = pmd_offset(pud_k, addr); > if (!pmd_present(*pmd_k)) { > no_context(regs, addr); > return; > } > - set_pmd(pmd, *pmd_k); > > /* > * Make sure the actual PTE exists as well to This looks good, but "Signed off by" lines are supposed to have real names associated with them and this looks like a handle to me. There also seems to be something broken with the email, as this is causing git to blow up, but for a small patch like this that's OK as I can resurrect it by hand. Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> # aside from the name Please send a v2 with the proper Signed off by line, as that's not something I'm supposed to just fix up myself. Thanks!
On 2022/2/23 5:25, Palmer Dabbelt wrote: > On Thu, 27 Jan 2022 02:06:22 PST (-0800), hanchuanhua@oppo.com wrote: >> Since all processes share the kernel address space, >> we only need to copy pgd in case of a vmalloc page >> fault exception, the other levels of page tables are >> shared, so the operation of copying pmd is unnecessary. >> >> Signed-off-by: hanchuanhua <hanchuanhua@oppo.com> >> --- >> arch/riscv/mm/fault.c | 10 +++------- >> 1 file changed, 3 insertions(+), 7 deletions(-) >> >> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c >> index 4e9efbe..40694f0 100644 >> --- a/arch/riscv/mm/fault.c >> +++ b/arch/riscv/mm/fault.c >> @@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code >> static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr) >> { >> pgd_t *pgd, *pgd_k; >> - pud_t *pud, *pud_k; >> - p4d_t *p4d, *p4d_k; >> - pmd_t *pmd, *pmd_k; >> + pud_t *pud_k; >> + p4d_t *p4d_k; >> + pmd_t *pmd_k; >> pte_t *pte_k; >> int index; >> unsigned long pfn; >> @@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a >> } >> set_pgd(pgd, *pgd_k); >> >> - p4d = p4d_offset(pgd, addr); >> p4d_k = p4d_offset(pgd_k, addr); >> 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)) { >> no_context(regs, addr); >> @@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a >> * Since the vmalloc area is global, it is unnecessary >> * to copy individual PTEs >> */ >> - pmd = pmd_offset(pud, addr); >> pmd_k = pmd_offset(pud_k, addr); >> if (!pmd_present(*pmd_k)) { >> no_context(regs, addr); >> return; >> } >> - set_pmd(pmd, *pmd_k); >> >> /* >> * Make sure the actual PTE exists as well to > This looks good, but "Signed off by" lines are supposed to have real > names associated with them and this looks like a handle to me. There > also seems to be something broken with the email, as this is causing git > to blow up, but for a small patch like this that's OK as I can resurrect > it by hand. > > Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> # aside from the name > > Please send a v2 with the proper Signed off by line, as that's not > something I'm supposed to just fix up myself. > > Thanks! First of all, thank you for your review and reply. I don't quite understand what's wrong with the line "Signed off by"? Thanks!
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 4e9efbe..40694f0 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr) { pgd_t *pgd, *pgd_k; - pud_t *pud, *pud_k; - p4d_t *p4d, *p4d_k; - pmd_t *pmd, *pmd_k; + pud_t *pud_k; + p4d_t *p4d_k; + pmd_t *pmd_k; pte_t *pte_k; int index; unsigned long pfn; @@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a } set_pgd(pgd, *pgd_k); - p4d = p4d_offset(pgd, addr); p4d_k = p4d_offset(pgd_k, addr); 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)) { no_context(regs, addr); @@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a * Since the vmalloc area is global, it is unnecessary * to copy individual PTEs */ - pmd = pmd_offset(pud, addr); pmd_k = pmd_offset(pud_k, addr); if (!pmd_present(*pmd_k)) { no_context(regs, addr); return; } - set_pmd(pmd, *pmd_k); /* * Make sure the actual PTE exists as well to
Since all processes share the kernel address space, we only need to copy pgd in case of a vmalloc page fault exception, the other levels of page tables are shared, so the operation of copying pmd is unnecessary. Signed-off-by: hanchuanhua <hanchuanhua@oppo.com> --- arch/riscv/mm/fault.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) -- 2.7.4