Hi, On 4/23/19 4:58 PM, Jakub Jermar wrote: > Hi Philippe! > > On 4/23/19 3:48 PM, Philippe Mathieu-Daudé wrote: >> Hi Jakub, >> >> On 4/23/19 1:00 PM, Jakub Jermář wrote: >>> This commit addresses QEMU Bug #1825311: >>> >>> mips_cpu_handle_mmu_fault renders all accessed pages executable >>> >>> It allows finer-grained control over whether the accessed page should be >>> executable by moving the decision to the underlying map_address >>> function, which has more information for this. >>> >>> As a result, pages that have the XI bit set in the TLB and are accessed >>> for read/write, don't suddenly end up being executable. >>> >> >> Fixes: https://bugs.launchpad.net/qemu/+bug/1825311 >> >>> Signed-off-by: Jakub Jermář <jakub.jer...@kernkonzept.com> >>> --- >>> target/mips/helper.c | 17 ++++++++++------- >>> 1 file changed, 10 insertions(+), 7 deletions(-) >>> >>> diff --git a/target/mips/helper.c b/target/mips/helper.c >>> index c44cdca3b5..132d073fbe 100644 >>> --- a/target/mips/helper.c >>> +++ b/target/mips/helper.c >>> @@ -43,7 +43,7 @@ int no_mmu_map_address (CPUMIPSState *env, hwaddr >>> *physical, int *prot, >>> target_ulong address, int rw, int access_type) >>> { >>> *physical = address; >>> - *prot = PAGE_READ | PAGE_WRITE; >>> + *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; >>> return TLBRET_MATCH; >>> } >>> >>> @@ -61,7 +61,7 @@ int fixed_mmu_map_address (CPUMIPSState *env, hwaddr >>> *physical, int *prot, >>> else >>> *physical = address; >>> >>> - *prot = PAGE_READ | PAGE_WRITE; >>> + *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; >>> return TLBRET_MATCH; >>> } >>> >>> @@ -101,6 +101,9 @@ int r4k_map_address (CPUMIPSState *env, hwaddr >>> *physical, int *prot, >>> *prot = PAGE_READ; >>> if (n ? tlb->D1 : tlb->D0) >>> *prot |= PAGE_WRITE; >>> + if (!(n ? tlb->XI1 : tlb->XI0)) { >>> + *prot |= PAGE_EXEC; >>> + } >> >> This was indeed missed in commit 2fb58b73746e. >> >>> return TLBRET_MATCH; >>> } >>> return TLBRET_DIRTY; >>> @@ -182,7 +185,7 @@ static int get_seg_physical_address(CPUMIPSState *env, >>> hwaddr *physical, >>> } else { >>> /* The segment is unmapped */ >>> *physical = physical_base | (real_address & segmask); >>> - *prot = PAGE_READ | PAGE_WRITE; >>> + *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; >>> return TLBRET_MATCH; >>> } >>> } >>> @@ -913,8 +916,8 @@ int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr >>> address, int size, int rw, >>> } >>> if (ret == TLBRET_MATCH) { >>> tlb_set_page(cs, address & TARGET_PAGE_MASK, >>> - physical & TARGET_PAGE_MASK, prot | PAGE_EXEC, >>> - mmu_idx, TARGET_PAGE_SIZE); >>> + physical & TARGET_PAGE_MASK, prot, mmu_idx, >>> + TARGET_PAGE_SIZE); >>> ret = 0; >>> } else if (ret < 0) >>> #endif >>> @@ -936,8 +939,8 @@ int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr >>> address, int size, int rw, >>> address, rw, access_type, >>> mmu_idx); >>> if (ret == TLBRET_MATCH) { >>> tlb_set_page(cs, address & TARGET_PAGE_MASK, >>> - physical & TARGET_PAGE_MASK, prot | PAGE_EXEC, >>> - mmu_idx, TARGET_PAGE_SIZE); >>> + physical & TARGET_PAGE_MASK, prot, mmu_idx, >>> + TARGET_PAGE_SIZE); >>> ret = 0; >>> return ret; >>> } >>> >> >> Your patch looks correct, but I'd like to test it. >> Do you have a reproducer? >> Can you describe the command line you used? > > I've just attached a reproducer image and script to the bug. It's a > 32-bit little-endian test binary running on top of the L4Re microkernel. > Let me know if you also need a 64-bit version. > > I tested both 32 and 64-bit versions of the reproducer and also checked > to see that the the other images I have lying around here (Linux 2.6.32 > big endian and HelenOS master little-endian, both 32-bit for 4Kc) > continue to run without regressions. > > Best regards, > Jakub
(ping) Is there anything else I can do to help to get this merged? https://patchew.org/QEMU/20190423110034.1260142-1-jakub.jer...@kernkonzept.com/ Thanks, Jakub -- Kernkonzept GmbH at Dresden, Germany, HRB 31129, CEO Dr.-Ing. Michael Hohmuth
