Hi, David, For non-Octeon CPU, htlb_info.huge_pte is equal to K0, but I don't know much about Octeon. So I think you know whether we should use K0 or htlb_info.huge_pte here, since you are the original author. On Thu, Jul 31, 2014 at 5:44 AM, David Daney <ddaney@xxxxxxxxxxxxxxxxxx> wrote: > On 07/30/2014 02:41 PM, James Hogan wrote: >> >> Hi Huacai, >> >> On Tuesday 29 July 2014 14:54:40 Huacai Chen wrote: >>> >>> In commit 2c8c53e28f1 (MIPS: Optimize TLB handlers for Octeon CPUs) >>> build_r4000_tlb_refill_handler() is modified. But it doesn't compatible >>> with the original code in HUGETLB case. Because there is a copy & paste >>> error and one line of code is missing. It is very easy to produce a bug >>> with LTP's hugemmap05 test. >>> >>> Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx> >>> Signed-off-by: Binbin Zhou <zhoubb@xxxxxxxxxx> >>> Cc: <stable@xxxxxxxxxxxxxxx> >>> --- >>> arch/mips/mm/tlbex.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c >>> index e80e10b..343fe0f 100644 >>> --- a/arch/mips/mm/tlbex.c >>> +++ b/arch/mips/mm/tlbex.c >>> @@ -1299,6 +1299,7 @@ static void build_r4000_tlb_refill_handler(void) >>> } >>> #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT >>> uasm_l_tlb_huge_update(&l, p); >>> + UASM_i_LW(&p, K0, 0, K1); >>> build_huge_update_entries(&p, htlb_info.huge_pte, K1); >>> build_huge_tlb_write_entry(&p, &l, &r, K0, tlb_random, >>> htlb_info.restore_scratch); >> >> >> build_huge_tlb_write_entry only uses K0 as a temp and clobbers without >> using >> the value, so the K0 must be being used by the code generated by >> build_huge_update_entires, but the patch you mentioned changed the second >> argument from K0 to htlb_info.huge_pte. >> >> So should the K0 in the new UASM_i_LW call be changed to >> htlb_info.huge_pte >> too? >> > > I don't know. You have to dump out the generated handler (by #define DEBUG > at the top of the file), then assemble/disassemble it. Looking at the > disassembly, we could make sensible statements about what is happening. > > > >> (David Daney on Cc) >> >> Thanks >> James >> > >
