Patchwork RISC-V: Add FP register core file support.

This adds fp reg support similar to the existing general reg support.

This fixes one gdb testsuite failure
FAIL: gdb.base/gcore.exp: corefile restored system registers
which fails without the patch because fcsr was missing.  Otherwise, no
regressions with riscv64-linux native testsuite run.

	gdb/
	* riscv-linux-tdep.c (riscv_linux_fregmap): New.
	(riscv_linux_fregset): New.
	(riscv_linux_iterate_over_regset_sections): Call cb for .reg2 section.
---
 gdb/riscv-linux-tdep.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

On 2/6/19 10:24 AM, Jim Wilson wrote:
> This adds fp reg support similar to the existing general reg support.
> 
> This fixes one gdb testsuite failure
> FAIL: gdb.base/gcore.exp: corefile restored system registers
> which fails without the patch because fcsr was missing.  Otherwise, no
> regressions with riscv64-linux native testsuite run.

Looks good to me.

* Jim Wilson <jimw@sifive.com> [2019-02-06 10:24:24 -0800]:

> This adds fp reg support similar to the existing general reg support.
> 
> This fixes one gdb testsuite failure
> FAIL: gdb.base/gcore.exp: corefile restored system registers
> which fails without the patch because fcsr was missing.  Otherwise, no
> regressions with riscv64-linux native testsuite run.
> 
> 	gdb/
> 	* riscv-linux-tdep.c (riscv_linux_fregmap): New.
> 	(riscv_linux_fregset): New.
> 	(riscv_linux_iterate_over_regset_sections): Call cb for .reg2
> 	section.

Looks good to me.

Thanks,
Andrew



> ---
>  gdb/riscv-linux-tdep.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/gdb/riscv-linux-tdep.c b/gdb/riscv-linux-tdep.c
> index e1f8e76567..91061c5b3e 100644
> --- a/gdb/riscv-linux-tdep.c
> +++ b/gdb/riscv-linux-tdep.c
> @@ -37,6 +37,16 @@ static const struct regcache_map_entry riscv_linux_gregmap[] =
>    { 0 }
>  };
>  
> +/* Define the FP register mapping.  The kernel puts the 32 FP regs first, and
> +   then FCSR.  */
> +
> +static const struct regcache_map_entry riscv_linux_fregmap[] =
> +{
> +  { 32, RISCV_FIRST_FP_REGNUM, 0 },
> +  { 1, RISCV_CSR_FCSR_REGNUM, 0 },
> +  { 0 }
> +};
> +
>  /* Define the general register regset.  */
>  
>  static const struct regset riscv_linux_gregset =
> @@ -44,6 +54,13 @@ static const struct regset riscv_linux_gregset =
>    riscv_linux_gregmap, regcache_supply_regset, regcache_collect_regset
>  };
>  
> +/* Define the FP register regset.  */
> +
> +static const struct regset riscv_linux_fregset =
> +{
> +  riscv_linux_fregmap, regcache_supply_regset, regcache_collect_regset
> +};
> +
>  /* Define hook for core file support.  */
>  
>  static void
> @@ -54,8 +71,10 @@ riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
>  {
>    cb (".reg", (32 * riscv_isa_xlen (gdbarch)), (32 * riscv_isa_xlen (gdbarch)),
>        &riscv_linux_gregset, NULL, cb_data);
> -
> -  /* TODO: Add FP register support.  */
> +  /* The kernel is adding 8 bytes for FCSR.  */
> +  cb (".reg2", (32 * riscv_isa_flen (gdbarch)) + 8,
> +      (32 * riscv_isa_flen (gdbarch)) + 8,
> +      &riscv_linux_fregset, NULL, cb_data);
>  }
>  
>  /* Signal trampoline support.  */
> -- 
> 2.17.1
>

On Fri, Feb 8, 2019 at 2:31 AM Andrew Burgess
<andrew.burgess@embecosm.com> wrote:
> * Jim Wilson <jimw@sifive.com> [2019-02-06 10:24:24 -0800]:
> >       gdb/
> >       * riscv-linux-tdep.c (riscv_linux_fregmap): New.
> >       (riscv_linux_fregset): New.
> >       (riscv_linux_iterate_over_regset_sections): Call cb for .reg2
> >       section.
>
> Looks good to me.

Thanks.  Committed.

Jim