| Message ID | 1539845066-31635-1-git-send-email-dayeol@berkeley.edu |
|---|---|
| State | New |
| Headers | show |
| Series | target/riscv/pmp.c: pmpcfg_csr_read return type demotion | expand |
On Wed, 17 Oct 2018 23:44:26 PDT (-0700), dayeol@berkeley.edu wrote: > There is a data type demotion bug in target/riscv/pmp.c > When the target_ulong is 8 bytes, pmpcfg_csr_read returns only lower 4 > bytes. This is missing at least the first requirement from https://wiki.qemu.org/Contribute/SubmitAPatch -- that's as far as I checked :). I can't take this one, please submit a v2. > --- > target/riscv/pmp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c > index c828950..4b6c20e 100644 > --- a/target/riscv/pmp.c > +++ b/target/riscv/pmp.c > @@ -337,7 +337,7 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) > > for (i = 0; i < sizeof(target_ulong); i++) { > val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i); > - cfg_val |= (val << (i * 8)); > + cfg_val |= ((target_ulong)val << ((target_ulong)i * 8)); > } > > PMP_DEBUG("hart " TARGET_FMT_ld ": reg%d, val: 0x" TARGET_FMT_lx, I believe this is correct: pmp_read_cfg() gives us the 8-bit PMP value, which then needs to be mixed together to form a single CSR value. The default promotion rules will result in an integer here ("i*8" is integer, which flows through) resulting in a 32-bit signed value on most hosts. That's obviously bogus on RV64I, with the high bits of the CSR being wrong. Aside from the metadata Reviewed-by: Palmer Dabbelt <palmer@sifive.com> Thanks!
Hi Lee, On 18/10/2018 08:44, Dayeol Lee wrote: > There is a data type demotion bug in target/riscv/pmp.c > When the target_ulong is 8 bytes, pmpcfg_csr_read returns only lower 4 > bytes. > --- > target/riscv/pmp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c > index c828950..4b6c20e 100644 > --- a/target/riscv/pmp.c > +++ b/target/riscv/pmp.c > @@ -337,7 +337,7 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) > > for (i = 0; i < sizeof(target_ulong); i++) { > val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i); > - cfg_val |= (val << (i * 8)); > + cfg_val |= ((target_ulong)val << ((target_ulong)i * 8)); Casting 'val' seems correct, however you don't need to cast the 'i'. Also you can remove the external parenthesis. > } > > PMP_DEBUG("hart " TARGET_FMT_ld ": reg%d, val: 0x" TARGET_FMT_lx, > Regards, Phil.
On 18 October 2018 at 18:37, Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > Hi Lee, > > On 18/10/2018 08:44, Dayeol Lee wrote: >> There is a data type demotion bug in target/riscv/pmp.c >> When the target_ulong is 8 bytes, pmpcfg_csr_read returns only lower 4 >> bytes. >> --- >> target/riscv/pmp.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c >> index c828950..4b6c20e 100644 >> --- a/target/riscv/pmp.c >> +++ b/target/riscv/pmp.c >> @@ -337,7 +337,7 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) >> >> for (i = 0; i < sizeof(target_ulong); i++) { >> val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i); >> - cfg_val |= (val << (i * 8)); >> + cfg_val |= ((target_ulong)val << ((target_ulong)i * 8)); > > Casting 'val' seems correct, however you don't need to cast the 'i'. You could just declare 'val' as a target_ulong to start with, and avoid the need for a cast at all, I think ? thanks -- PMM
On 18/10/2018 19:44, Peter Maydell wrote: > On 18 October 2018 at 18:37, Philippe Mathieu-Daudé <philmd@redhat.com> wrote: >> Hi Lee, >> >> On 18/10/2018 08:44, Dayeol Lee wrote: >>> There is a data type demotion bug in target/riscv/pmp.c >>> When the target_ulong is 8 bytes, pmpcfg_csr_read returns only lower 4 >>> bytes. >>> --- >>> target/riscv/pmp.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c >>> index c828950..4b6c20e 100644 >>> --- a/target/riscv/pmp.c >>> +++ b/target/riscv/pmp.c >>> @@ -337,7 +337,7 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) >>> >>> for (i = 0; i < sizeof(target_ulong); i++) { >>> val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i); >>> - cfg_val |= (val << (i * 8)); >>> + cfg_val |= ((target_ulong)val << ((target_ulong)i * 8)); >> >> Casting 'val' seems correct, however you don't need to cast the 'i'. > > You could just declare 'val' as a target_ulong to start with, > and avoid the need for a cast at all, I think ? I did not look at the whole code, just the patch context. Now looking at the code this is obvious ;) Thanks Peter!
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c index c828950..4b6c20e 100644 --- a/target/riscv/pmp.c +++ b/target/riscv/pmp.c @@ -337,7 +337,7 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index) for (i = 0; i < sizeof(target_ulong); i++) { val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i); - cfg_val |= (val << (i * 8)); + cfg_val |= ((target_ulong)val << ((target_ulong)i * 8)); } PMP_DEBUG("hart " TARGET_FMT_ld ": reg%d, val: 0x" TARGET_FMT_lx,