| Message ID | 20190828231651.17176-5-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | exec: Cleanup watchpoints | expand |
On 8/29/19 1:16 AM, Richard Henderson wrote: > We want to move the check for watchpoints from > memory_region_section_get_iotlb to tlb_set_page_with_attrs. > Isolate the loop over watchpoints to an exported function. > > Rename the existing cpu_watchpoint_address_matches to > watchpoint_address_matches, since it doesn't actually > have a cpu argument. > > Reviewed-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/hw/core/cpu.h | 7 +++++++ > exec.c | 45 ++++++++++++++++++++++++++++--------------- > 2 files changed, 36 insertions(+), 16 deletions(-) > > diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h > index 7bd8bed5b2..c7cda65c66 100644 > --- a/include/hw/core/cpu.h > +++ b/include/hw/core/cpu.h > @@ -1096,6 +1096,12 @@ static inline void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > MemTxAttrs atr, int fl, uintptr_t ra) > { > } > + > +static inline int cpu_watchpoint_address_matches(CPUState *cpu, > + vaddr addr, vaddr len) > +{ > + return 0; > +} > #else > int cpu_watchpoint_insert(CPUState *cpu, vaddr addr, vaddr len, > int flags, CPUWatchpoint **watchpoint); > @@ -1105,6 +1111,7 @@ void cpu_watchpoint_remove_by_ref(CPUState *cpu, CPUWatchpoint *watchpoint); > void cpu_watchpoint_remove_all(CPUState *cpu, int mask); > void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > MemTxAttrs attrs, int flags, uintptr_t ra); > +int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len); > #endif > > /** > diff --git a/exec.c b/exec.c > index cb6f5763dc..8575ce51ad 100644 > --- a/exec.c > +++ b/exec.c > @@ -1138,9 +1138,8 @@ void cpu_watchpoint_remove_all(CPUState *cpu, int mask) > * partially or completely with the address range covered by the > * access). > */ > -static inline bool cpu_watchpoint_address_matches(CPUWatchpoint *wp, > - vaddr addr, > - vaddr len) > +static inline bool watchpoint_address_matches(CPUWatchpoint *wp, > + vaddr addr, vaddr len) > { > /* We know the lengths are non-zero, but a little caution is > * required to avoid errors in the case where the range ends > @@ -1152,6 +1151,20 @@ static inline bool cpu_watchpoint_address_matches(CPUWatchpoint *wp, > > return !(addr > wpend || wp->vaddr > addrend); > } > + > +/* Return flags for watchpoints that match addr + prot. */ > +int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len) > +{ > + CPUWatchpoint *wp; > + int ret = 0; > + > + QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { > + if (watchpoint_address_matches(wp, addr, TARGET_PAGE_SIZE)) { > + ret |= wp->flags; > + } > + } > + return ret; > +} > #endif /* !CONFIG_USER_ONLY */ > > /* Add a breakpoint. */ > @@ -1459,7 +1472,7 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu, > target_ulong *address) > { > hwaddr iotlb; > - CPUWatchpoint *wp; > + int flags, match; > > if (memory_region_is_ram(section->mr)) { > /* Normal RAM. */ > @@ -1477,17 +1490,17 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu, > iotlb += xlat; > } > > - /* Make accesses to pages with watchpoints go via the > - watchpoint trap routines. */ > - QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { > - if (cpu_watchpoint_address_matches(wp, vaddr, TARGET_PAGE_SIZE)) { > - /* Avoid trapping reads of pages with a write breakpoint. */ > - if ((prot & PAGE_WRITE) || (wp->flags & BP_MEM_READ)) { > - iotlb = PHYS_SECTION_WATCH + paddr; > - *address |= TLB_MMIO; > - break; > - } > - } > + /* Avoid trapping reads of pages with a write breakpoint. */ > + match = (prot & PAGE_READ ? BP_MEM_READ : 0) > + | (prot & PAGE_WRITE ? BP_MEM_WRITE : 0); Isn't it cheaper to do here: if (!match) { return iotlb; } or if (match) { > + flags = cpu_watchpoint_address_matches(cpu, vaddr, TARGET_PAGE_SIZE); > + if (flags & match) { > + /* > + * Make accesses to pages with watchpoints go via the > + * watchpoint trap routines. > + */ > + iotlb = PHYS_SECTION_WATCH + paddr; > + *address |= TLB_MMIO; > } } Regardless: Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> > return iotlb; > @@ -2806,7 +2819,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > > addr = cc->adjust_watchpoint_address(cpu, addr, len); > QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { > - if (cpu_watchpoint_address_matches(wp, addr, len) > + if (watchpoint_address_matches(wp, addr, len) > && (wp->flags & flags)) { > if (flags == BP_MEM_READ) { > wp->flags |= BP_WATCHPOINT_HIT_READ; >
On 8/29/19 10:20 AM, Philippe Mathieu-Daudé wrote: >> + /* Avoid trapping reads of pages with a write breakpoint. */ >> + match = (prot & PAGE_READ ? BP_MEM_READ : 0) >> + | (prot & PAGE_WRITE ? BP_MEM_WRITE : 0); > > Isn't it cheaper to do here: > > if (!match) { > return iotlb; > } > > or > > if (match) { Note that PROT_NONE pages never reach here; they always trap in tlb_fill. The only way we can get match == 0 here is for the case of an execute-only page. Which is possible, but extremely unlikely. Almost all targets merge the text and rodata sections, which means that virtually all executable pages are also readable. (Although I must say that in this age of ROP-gadgets, leaving the rodata section executable is probably a mistake, and tools should be updated to *not* merge them. That's still not necessarily execute-only for the text section, but I don't see anything in principal that would prevent it.) r~
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 7bd8bed5b2..c7cda65c66 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -1096,6 +1096,12 @@ static inline void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, MemTxAttrs atr, int fl, uintptr_t ra) { } + +static inline int cpu_watchpoint_address_matches(CPUState *cpu, + vaddr addr, vaddr len) +{ + return 0; +} #else int cpu_watchpoint_insert(CPUState *cpu, vaddr addr, vaddr len, int flags, CPUWatchpoint **watchpoint); @@ -1105,6 +1111,7 @@ void cpu_watchpoint_remove_by_ref(CPUState *cpu, CPUWatchpoint *watchpoint); void cpu_watchpoint_remove_all(CPUState *cpu, int mask); void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, MemTxAttrs attrs, int flags, uintptr_t ra); +int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len); #endif /** diff --git a/exec.c b/exec.c index cb6f5763dc..8575ce51ad 100644 --- a/exec.c +++ b/exec.c @@ -1138,9 +1138,8 @@ void cpu_watchpoint_remove_all(CPUState *cpu, int mask) * partially or completely with the address range covered by the * access). */ -static inline bool cpu_watchpoint_address_matches(CPUWatchpoint *wp, - vaddr addr, - vaddr len) +static inline bool watchpoint_address_matches(CPUWatchpoint *wp, + vaddr addr, vaddr len) { /* We know the lengths are non-zero, but a little caution is * required to avoid errors in the case where the range ends @@ -1152,6 +1151,20 @@ static inline bool cpu_watchpoint_address_matches(CPUWatchpoint *wp, return !(addr > wpend || wp->vaddr > addrend); } + +/* Return flags for watchpoints that match addr + prot. */ +int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len) +{ + CPUWatchpoint *wp; + int ret = 0; + + QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { + if (watchpoint_address_matches(wp, addr, TARGET_PAGE_SIZE)) { + ret |= wp->flags; + } + } + return ret; +} #endif /* !CONFIG_USER_ONLY */ /* Add a breakpoint. */ @@ -1459,7 +1472,7 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu, target_ulong *address) { hwaddr iotlb; - CPUWatchpoint *wp; + int flags, match; if (memory_region_is_ram(section->mr)) { /* Normal RAM. */ @@ -1477,17 +1490,17 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu, iotlb += xlat; } - /* Make accesses to pages with watchpoints go via the - watchpoint trap routines. */ - QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { - if (cpu_watchpoint_address_matches(wp, vaddr, TARGET_PAGE_SIZE)) { - /* Avoid trapping reads of pages with a write breakpoint. */ - if ((prot & PAGE_WRITE) || (wp->flags & BP_MEM_READ)) { - iotlb = PHYS_SECTION_WATCH + paddr; - *address |= TLB_MMIO; - break; - } - } + /* Avoid trapping reads of pages with a write breakpoint. */ + match = (prot & PAGE_READ ? BP_MEM_READ : 0) + | (prot & PAGE_WRITE ? BP_MEM_WRITE : 0); + flags = cpu_watchpoint_address_matches(cpu, vaddr, TARGET_PAGE_SIZE); + if (flags & match) { + /* + * Make accesses to pages with watchpoints go via the + * watchpoint trap routines. + */ + iotlb = PHYS_SECTION_WATCH + paddr; + *address |= TLB_MMIO; } return iotlb; @@ -2806,7 +2819,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, addr = cc->adjust_watchpoint_address(cpu, addr, len); QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { - if (cpu_watchpoint_address_matches(wp, addr, len) + if (watchpoint_address_matches(wp, addr, len) && (wp->flags & flags)) { if (flags == BP_MEM_READ) { wp->flags |= BP_WATCHPOINT_HIT_READ;