[PATCH] gdbserver/s390: Enable high GPRs, VX, TDB with 31-bit gdbserver.
Marcin Kościelnicki
koriakin@0x04.net
Mon Feb 22 00:56:00 GMT 2016
On 12/02/16 20:57, Marcin Kościelnicki wrote:
> Currently, 31-bit gdbserver doesn't support collecting/supplying high
> GPRs, VX registers, and TDB data. This is not much of a problem now,
> since machines that have them usually have a 64-bit gdbserver that can
> be used to debug 31-bit targets just fine. However, with fast
> tracepoints, it's not possible to use a 64-bit gdbserver with a 31-bit
> IPA (and thus a 31-bit target), so 31-bit gdbserver has to be used
> for 31-bit targets. Thus, this patch is needed to allow collecting
> high GPRs and VX registers on 31-bit targets via fast tracepoints.
>
> gdb/gdbserver/ChangeLog:
>
> * linux-s390-low.c (s390_num_regs_3264): Define on 31-bit too.
> (s390_regmap_3264) [!__s390x__]: New global.
> (s390_collect_ptrace_register): Skip map entries containing -1.
> (s390_supply_ptrace_register): Ditto.
> (s390_fill_gprs_high): New function.
> (s390_store_gprs_high): New function.
> (s390_regsets): Add NT_S390_HIGH_GPRS.
> (s390_get_hwcap): Enable on 31-bit.
> (have_hwcap_s390_high_gprs): Enable on 31-bit.
> (s390_arch_setup): Enable detection of high GPRs, TDB, VX on 31-bit.
> Detect NT_S390_HIGH_GPRS.
> (s390_usrregs_info_3264): Enable on 31-bit.
> (s390_regs_info): Enable regs_info_3264 on 31-bit.
> (initialize_low_arch): Initialize s390_regsets_info_3264 on 31-bit.
> ---
> As mentioned in the s390 fast tracepoint thread, here comes a patch for
> proper high GPR support (and VX+TDB while we're at it) in 31-bit
> gdbserver. It's mostly removing ifdefs for __s390x__ - the only
> nontrivial part is the new regmap (with -1s for $rXh since they are not
> in the basic register set), and the new regset.
>
> Tests have been run (RHEL 7.2, configured for s390-ibm-linux-gnu on a 64-bit
> kernel)), and it's a mixed bag. A few new failures are present:
>
> native-gdbserver: gdb.base/store.exp: up struct 1 u; print new u, expecting {s = \{1}}
> native-gdbserver: gdb.base/store.exp: up struct 1 u; set u to s_1
> native-gdbserver: gdb.base/store.exp: up struct 2 u; print new u, expecting {s = \{1, 2}}
> native-gdbserver: gdb.base/store.exp: up struct 2 u; set u to s_2
> native-gdbserver: gdb.base/store.exp: upvar charest l; print new l, expecting 4 ..004.
> native-gdbserver: gdb.base/store.exp: upvar charest l; set l to 4
> native-gdbserver: gdb.base/store.exp: upvar int l; print new l, expecting 4
> native-gdbserver: gdb.base/store.exp: upvar int l; set l to 4
> native-gdbserver: gdb.base/store.exp: upvar long l; print new l, expecting 4
> native-gdbserver: gdb.base/store.exp: upvar long l; set l to 4
> native-gdbserver: gdb.base/store.exp: upvar longest l; print new l, expecting 4
> native-gdbserver: gdb.base/store.exp: upvar longest l; set l to 4
> native-gdbserver: gdb.base/store.exp: upvar short l; print new l, expecting 4
> native-gdbserver: gdb.base/store.exp: upvar short l; set l to 4
>
> However, these failures are already present on 64-bit gdbserver with
> -m31 target, so they're not really new. On the other hand, if -mzarch
> is included in CFLAGS, this patch fixes a few failures:
>
> native-gdbserver: gdb.base/gdb1090.exp: print s24
> native-gdbserver: gdb.base/store.exp: up struct 4 u; print old u, expecting {s = \{0, 0, 0, 0}}
> native-gdbserver: gdb.base/store.exp: var longest l; print old l, expecting -1
> native-gdbserver: gdb.base/store.exp: var struct 4 u; print old u, expecting {s = \{0, 0, 0, 0}}
>
> So, I suppose we should look into the store.exp failures, there's a bug
> in there somewhere...
Ping.
I've looked at store.exp. Basically, it attempts a store to a register
variable (in %r12) of an inactive frame. Since it's a 31-bit target,
only low 32 bits of %r12 are stored (which is just fine, since it's a
32-bit variable or smaller). If there are no high GPRs, the unwinder
returns a proper memory lvalue, and everything works fine. However, if
there are high GPRs, unwinding %r12 results in a memory reference cast
to a 64-bit int (s390_unwind_pseudo_register) - since that's not an
lvalue, the store fails.
I'm not sure how that could be fixed, any ideas?
>
> gdb/gdbserver/ChangeLog | 18 +++++++
> gdb/gdbserver/linux-s390-low.c | 105 +++++++++++++++++++++++++++++++----------
> 2 files changed, 97 insertions(+), 26 deletions(-)
>
> diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
> index ca82f91..d5162df 100644
> --- a/gdb/gdbserver/ChangeLog
> +++ b/gdb/gdbserver/ChangeLog
> @@ -1,5 +1,23 @@
> 2016-02-12 Marcin Kościelnicki <koriakin@0x04.net>
>
> + * linux-s390-low.c (s390_num_regs_3264): Define on 31-bit too.
> + (s390_regmap_3264) [!__s390x__]: New global.
> + (s390_collect_ptrace_register): Skip map entries containing -1.
> + (s390_supply_ptrace_register): Ditto.
> + (s390_fill_gprs_high): New function.
> + (s390_store_gprs_high): New function.
> + (s390_regsets): Add NT_S390_HIGH_GPRS.
> + (s390_get_hwcap): Enable on 31-bit.
> + (have_hwcap_s390_high_gprs): Enable on 31-bit.
> + (s390_arch_setup): Enable detection of high GPRs, TDB, VX on 31-bit.
> + Detect NT_S390_HIGH_GPRS.
> + (s390_usrregs_info_3264): Enable on 31-bit.
> + (s390_regs_info): Enable regs_info_3264 on 31-bit.
> + (initialize_low_arch): Initialize s390_regsets_info_3264 on 31-bit.
> +
> +
> +2016-02-12 Marcin Kościelnicki <koriakin@0x04.net>
> +
> * tracepoint.c (x_tracepoint_action_download): Change
> write_inferior_data_ptr to write_inferior_data_pointer.
> (cmd_qtstart): Likewise.
> diff --git a/gdb/gdbserver/linux-s390-low.c b/gdb/gdbserver/linux-s390-low.c
> index 63728aa..116042e 100644
> --- a/gdb/gdbserver/linux-s390-low.c
> +++ b/gdb/gdbserver/linux-s390-low.c
> @@ -132,9 +132,9 @@ static int s390_regmap[] = {
> PT_ORIGGPR2,
> };
>
> -#ifdef __s390x__
> #define s390_num_regs_3264 68
>
> +#ifdef __s390x__
> static int s390_regmap_3264[] = {
> PT_PSWMASK, PT_PSWADDR,
>
> @@ -161,6 +161,33 @@ static int s390_regmap_3264[] = {
>
> PT_ORIGGPR2,
> };
> +#else
> +static int s390_regmap_3264[] = {
> + PT_PSWMASK, PT_PSWADDR,
> +
> + -1, PT_GPR0, -1, PT_GPR1,
> + -1, PT_GPR2, -1, PT_GPR3,
> + -1, PT_GPR4, -1, PT_GPR5,
> + -1, PT_GPR6, -1, PT_GPR7,
> + -1, PT_GPR8, -1, PT_GPR9,
> + -1, PT_GPR10, -1, PT_GPR11,
> + -1, PT_GPR12, -1, PT_GPR13,
> + -1, PT_GPR14, -1, PT_GPR15,
> +
> + PT_ACR0, PT_ACR1, PT_ACR2, PT_ACR3,
> + PT_ACR4, PT_ACR5, PT_ACR6, PT_ACR7,
> + PT_ACR8, PT_ACR9, PT_ACR10, PT_ACR11,
> + PT_ACR12, PT_ACR13, PT_ACR14, PT_ACR15,
> +
> + PT_FPC,
> +
> + PT_FPR0_HI, PT_FPR1_HI, PT_FPR2_HI, PT_FPR3_HI,
> + PT_FPR4_HI, PT_FPR5_HI, PT_FPR6_HI, PT_FPR7_HI,
> + PT_FPR8_HI, PT_FPR9_HI, PT_FPR10_HI, PT_FPR11_HI,
> + PT_FPR12_HI, PT_FPR13_HI, PT_FPR14_HI, PT_FPR15_HI,
> +
> + PT_ORIGGPR2,
> +};
> #endif
>
>
> @@ -180,12 +207,12 @@ static void
> s390_collect_ptrace_register (struct regcache *regcache, int regno, char *buf)
> {
> int size = register_size (regcache->tdesc, regno);
> + const struct regs_info *regs_info = (*the_low_target.regs_info) ();
> + struct usrregs_info *usr = regs_info->usrregs;
> + int regaddr = usr->regmap[regno];
> +
> if (size < sizeof (long))
> {
> - const struct regs_info *regs_info = (*the_low_target.regs_info) ();
> - struct usrregs_info *usr = regs_info->usrregs;
> - int regaddr = usr->regmap[regno];
> -
> memset (buf, 0, sizeof (long));
>
> if ((regno ^ 1) < usr->num_regs
> @@ -218,7 +245,7 @@ s390_collect_ptrace_register (struct regcache *regcache, int regno, char *buf)
> else
> collect_register (regcache, regno, buf);
> }
> - else
> + else if (regaddr != -1)
> collect_register (regcache, regno, buf);
> }
>
> @@ -227,12 +254,12 @@ s390_supply_ptrace_register (struct regcache *regcache,
> int regno, const char *buf)
> {
> int size = register_size (regcache->tdesc, regno);
> + const struct regs_info *regs_info = (*the_low_target.regs_info) ();
> + struct usrregs_info *usr = regs_info->usrregs;
> + int regaddr = usr->regmap[regno];
> +
> if (size < sizeof (long))
> {
> - const struct regs_info *regs_info = (*the_low_target.regs_info) ();
> - struct usrregs_info *usr = regs_info->usrregs;
> - int regaddr = usr->regmap[regno];
> -
> if ((regno ^ 1) < usr->num_regs
> && usr->regmap[regno ^ 1] == regaddr)
> {
> @@ -274,7 +301,7 @@ s390_supply_ptrace_register (struct regcache *regcache,
> else
> supply_register (regcache, regno, buf);
> }
> - else
> + else if (regaddr != -1)
> supply_register (regcache, regno, buf);
> }
>
> @@ -301,6 +328,28 @@ s390_fill_gregset (struct regcache *regcache, void *buf)
>
> /* Fill and store functions for extended register sets. */
>
> +#ifndef __s390x__
> +static void
> +s390_fill_gprs_high (struct regcache *regcache, void *buf)
> +{
> + int r0h = find_regno (regcache->tdesc, "r0h");
> + int i;
> +
> + for (i = 0; i < 16; i++)
> + collect_register (regcache, r0h + 2 * i, (char *) buf + 4 * i);
> +}
> +
> +static void
> +s390_store_gprs_high (struct regcache *regcache, const void *buf)
> +{
> + int r0h = find_regno (regcache->tdesc, "r0h");
> + int i;
> +
> + for (i = 0; i < 16; i++)
> + supply_register (regcache, r0h + 2 * i, (const char *) buf + 4 * i);
> +}
> +#endif
> +
> static void
> s390_store_last_break (struct regcache *regcache, const void *buf)
> {
> @@ -378,6 +427,10 @@ s390_store_vxrs_high (struct regcache *regcache, const void *buf)
>
> static struct regset_info s390_regsets[] = {
> { 0, 0, 0, 0, GENERAL_REGS, s390_fill_gregset, NULL },
> +#ifndef __s390x__
> + { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_S390_HIGH_GPRS, 0,
> + EXTENDED_REGS, s390_fill_gprs_high, s390_store_gprs_high },
> +#endif
> /* Last break address is read-only; no fill function. */
> { PTRACE_GETREGSET, -1, NT_S390_LAST_BREAK, 0, EXTENDED_REGS,
> NULL, s390_store_last_break },
> @@ -440,7 +493,6 @@ s390_set_pc (struct regcache *regcache, CORE_ADDR newpc)
> }
> }
>
> -#ifdef __s390x__
> static unsigned long
> s390_get_hwcap (const struct target_desc *tdesc)
> {
> @@ -468,7 +520,6 @@ s390_get_hwcap (const struct target_desc *tdesc)
>
> return 0;
> }
> -#endif
>
> static int
> s390_check_regset (int pid, int regset, int regsize)
> @@ -485,11 +536,9 @@ s390_check_regset (int pid, int regset, int regsize)
> return 0;
> }
>
> -#ifdef __s390x__
> /* For a 31-bit inferior, whether the kernel supports using the full
> 64-bit GPRs. */
> static int have_hwcap_s390_high_gprs = 0;
> -#endif
>
> static void
> s390_arch_setup (void)
> @@ -517,8 +566,8 @@ s390_arch_setup (void)
>
> /* On a 64-bit host, check the low bit of the (31-bit) PSWM
> -- if this is one, we actually have a 64-bit inferior. */
> -#ifdef __s390x__
> {
> +#ifdef __s390x__
> unsigned int pswm;
> struct regcache *regcache = new_register_cache (tdesc);
>
> @@ -550,7 +599,9 @@ s390_arch_setup (void)
>
> /* For a 31-bit inferior, check whether the kernel supports
> using the full 64-bit GPRs. */
> - else if (s390_get_hwcap (tdesc) & HWCAP_S390_HIGH_GPRS)
> + else
> +#endif
> + if (s390_get_hwcap (tdesc) & HWCAP_S390_HIGH_GPRS)
> {
> have_hwcap_s390_high_gprs = 1;
> if (have_regset_tdb)
> @@ -571,18 +622,22 @@ s390_arch_setup (void)
> tdesc = tdesc_s390_linux64;
> }
> }
> -#endif
>
> /* Update target_regsets according to available register sets. */
> for (regset = s390_regsets; regset->size >= 0; regset++)
> if (regset->get_request == PTRACE_GETREGSET)
> switch (regset->nt_type)
> {
> +#ifndef __s390x__
> + case NT_S390_HIGH_GPRS:
> + regset->size = have_hwcap_s390_high_gprs ? 64 : 0;
> + break;
> +#endif
> case NT_S390_LAST_BREAK:
> - regset->size = have_regset_last_break? 8 : 0;
> + regset->size = have_regset_last_break ? 8 : 0;
> break;
> case NT_S390_SYSTEM_CALL:
> - regset->size = have_regset_system_call? 4 : 0;
> + regset->size = have_regset_system_call ? 4 : 0;
> break;
> case NT_S390_TDB:
> regset->size = have_regset_tdb ? 256 : 0;
> @@ -637,7 +692,6 @@ static struct regs_info regs_info =
> &s390_regsets_info
> };
>
> -#ifdef __s390x__
> static struct usrregs_info s390_usrregs_info_3264 =
> {
> s390_num_regs_3264,
> @@ -657,20 +711,21 @@ static struct regs_info regs_info_3264 =
> &s390_usrregs_info_3264,
> &s390_regsets_info_3264
> };
> -#endif
>
> static const struct regs_info *
> s390_regs_info (void)
> {
> -#ifdef __s390x__
> if (have_hwcap_s390_high_gprs)
> {
> +#ifdef __s390x__
> const struct target_desc *tdesc = current_process ()->tdesc;
>
> if (register_size (tdesc, 0) == 4)
> return ®s_info_3264;
> - }
> +#else
> + return ®s_info_3264;
> #endif
> + }
> return ®s_info;
> }
>
> @@ -732,7 +787,5 @@ initialize_low_arch (void)
> init_registers_s390x_tevx_linux64 ();
>
> initialize_regsets_info (&s390_regsets_info);
> -#ifdef __s390x__
> initialize_regsets_info (&s390_regsets_info_3264);
> -#endif
> }
>
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