On Thu, May 14, 2020 at 3:46 PM Christophe Leroy <christophe.le...@csgroup.eu> wrote: > > > > Le 06/05/2020 à 05:40, Jordan Niethe a écrit : > > Introduce a probe_user_read_inst() function to use in cases where > > probe_user_read() is used for getting an instruction. This will be more > > useful for prefixed instructions. > > > > Reviewed-by: Alistair Popple <alist...@popple.id.au> > > Signed-off-by: Jordan Niethe <jniet...@gmail.com> > > --- > > v6: - New to series > > --- > > arch/powerpc/include/asm/inst.h | 3 +++ > > arch/powerpc/lib/Makefile | 2 +- > > arch/powerpc/lib/inst.c | 18 ++++++++++++++++++ > > arch/powerpc/mm/fault.c | 2 +- > > 4 files changed, 23 insertions(+), 2 deletions(-) > > create mode 100644 arch/powerpc/lib/inst.c > > > > diff --git a/arch/powerpc/include/asm/inst.h > > b/arch/powerpc/include/asm/inst.h > > index 552e953bf04f..3e9a58420151 100644 > > --- a/arch/powerpc/include/asm/inst.h > > +++ b/arch/powerpc/include/asm/inst.h > > @@ -37,4 +37,7 @@ static inline bool ppc_inst_equal(struct ppc_inst x, > > struct ppc_inst y) > > return ppc_inst_val(x) == ppc_inst_val(y); > > } > > > > +int probe_user_read_inst(struct ppc_inst *inst, > > + struct ppc_inst *nip); > > + > > #endif /* _ASM_INST_H */ > > diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile > > index b8de3be10eb4..546591848219 100644 > > --- a/arch/powerpc/lib/Makefile > > +++ b/arch/powerpc/lib/Makefile > > @@ -16,7 +16,7 @@ CFLAGS_code-patching.o += -DDISABLE_BRANCH_PROFILING > > CFLAGS_feature-fixups.o += -DDISABLE_BRANCH_PROFILING > > endif > > > > -obj-y += alloc.o code-patching.o feature-fixups.o pmem.o > > +obj-y += alloc.o code-patching.o feature-fixups.o pmem.o inst.o > > > > ifndef CONFIG_KASAN > > obj-y += string.o memcmp_$(BITS).o > > diff --git a/arch/powerpc/lib/inst.c b/arch/powerpc/lib/inst.c > > new file mode 100644 > > index 000000000000..eaf786afad2b > > --- /dev/null > > +++ b/arch/powerpc/lib/inst.c > > @@ -0,0 +1,18 @@ > > +// SPDX-License-Identifier: GPL-2.0-or-later > > +/* > > + * Copyright 2020, IBM Corporation. > > + */ > > + > > +#include <linux/uaccess.h> > > +#include <asm/inst.h> > > + > > +int probe_user_read_inst(struct ppc_inst *inst, > > + struct ppc_inst *nip) > > +{ > > + unsigned int val; > > + int err; > > + > > + err = probe_user_read(&val, nip, sizeof(val)); > > + *inst = ppc_inst(val); > > + return err; > > +} > > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > > index 4a50f125ec18..f3a943eae305 100644 > > --- a/arch/powerpc/mm/fault.c > > +++ b/arch/powerpc/mm/fault.c > > @@ -281,7 +281,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, > > unsigned long address, > > access_ok(nip, sizeof(*nip))) { > > struct ppc_inst inst; > > > > - if (!probe_user_read(&inst, nip, sizeof(inst))) > > + if (!probe_user_read_inst(&inst, (struct ppc_inst > > __user *)nip)) > > Shouldn't 'nip' become de 'struct ppc_inst __user *' instead of casting ? > > > return !store_updates_sp(inst); > > *must_retry = true; > > } > > Yeah it would make more sense to do it like this. --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -256,7 +256,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address, * expand to 1MB without further checks. */ if (address + 0x100000 < vma->vm_end) { - unsigned int __user *nip = (unsigned int __user *)regs->nip; + struct ppc_inst __user *nip = (struct ppc_inst __user *)regs->nip; /* get user regs even if this fault is in kernel mode */ struct pt_regs *uregs = current->thread.regs; if (uregs == NULL) @@ -281,7 +281,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address, access_ok(nip, sizeof(*nip))) { struct ppc_inst inst;
- if (!probe_user_read_inst(&inst, (struct ppc_inst __user *)nip)) + if (!probe_user_read_inst(&inst, nip)) return !store_updates_sp(inst); *must_retry = true; } -- 2.17.1 > > Christophe