[PATCH v11 06/27] powerpc/ptrace: Enable support for NT_PPC_CVMX

wei.guo.simon
2016-07-17T02:01:45Z

This patch enables support for TM checkpointed VMX register
set ELF core note NT_PPC_CVMX based ptrace requests through
PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved
through adding a register set REGSET_CVMX in powerpc
corresponding to the ELF core note section added. It
implements the get, set and active functions for this new
register set added.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Cyril Bur <cyrilbur@gmail.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Simon Guo <wei.guo.simon@gmail.com>
Cc: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Rashmica Gupta <rashmicy@gmail.com>
Cc: Khem Raj <raj.khem@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Cc: Chris Smart <chris@distroguy.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
---
arch/powerpc/include/uapi/asm/elf.h | 1 +
arch/powerpc/kernel/ptrace.c | 158 ++++++++++++++++++++++++++++++++++++
2 files changed, 159 insertions(+)

diff --git a/arch/powerpc/include/uapi/asm/elf.h b/arch/powerpc/include/uapi/asm/elf.h
index c2d21d1..ecb4e84 100644
--- a/arch/powerpc/include/uapi/asm/elf.h
+++ b/arch/powerpc/include/uapi/asm/elf.h
@@ -91,6 +91,7 @@

#define ELF_NGREG 48 /* includes nip, msr, lr, etc. */
#define ELF_NFPREG 33 /* includes fpscr */
+#define ELF_NVMX 34 /* includes all vector registers */

typedef unsigned long elf_greg_t64;
typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG];
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index a3d4bad..a2cf240 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -64,6 +64,8 @@ struct pt_regs_offset {
{.name = STR(gpr##num), .offset = offsetof(struct pt_regs, gpr[num])}
#define REG_OFFSET_END {.name = NULL, .offset = 0}

+#define TVSO(f) (offsetof(struct thread_vr_state, f))
+
static const struct pt_regs_offset regoffset_table[] = {
GPR_OFFSET_NAME(0),
GPR_OFFSET_NAME(1),
@@ -914,6 +916,151 @@ static int tm_cfpr_set(struct task_struct *target,
target->thread.ckfp_state.fpscr = buf[32];
return 0;
}
+
+/**
+ * tm_cvmx_active - get active number of registers in CVMX
+ * @target: The target task.
+ * @regset: The user regset structure.
+ *
+ * This function checks for the active number of available
+ * regisers in checkpointed VMX category.
+ */
+static int tm_cvmx_active(struct task_struct *target,
+ const struct user_regset *regset)
+{
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return 0;
+
+ return regset->n;
+}
+
+/**
+ * tm_cvmx_get - get CMVX registers
+ * @target: The target task.
+ * @regset: The user regset structure.
+ * @pos: The buffer position.
+ * @count: Number of bytes to copy.
+ * @kbuf: Kernel buffer to copy from.
+ * @ubuf: User buffer to copy into.
+ *
+ * This function gets in transaction checkpointed VMX registers.
+ *
+ * When the transaction is active 'ckvr_state' and 'ckvr_save' hold
+ * the checkpointed values for the current transaction to fall
+ * back on if it aborts in between. The userspace interface buffer
+ * layout is as follows.
+ *
+ * struct data {
+ * vector128 vr[32];
+ * vector128 vscr;
+ * vector128 vrsave;
+ *};
+ */
+static int tm_cvmx_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ int ret;
+
+ BUILD_BUG_ON(TVSO(vscr) != TVSO(vr[32]));
+
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return -ENODATA;
+
+ /* Flush the state */
+ flush_fp_to_thread(target);
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ &target->thread.ckvr_state, 0,
+ 33 * sizeof(vector128));
+ if (!ret) {
+ /*
+ * Copy out only the low-order word of vrsave.
+ */
+ union {
+ elf_vrreg_t reg;
+ u32 word;
+ } vrsave;
+ memset(&vrsave, 0, sizeof(vrsave));
+ vrsave.word = target->thread.ckvrsave;
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
+ 33 * sizeof(vector128), -1);
+ }
+
+ return ret;
+}
+
+/**
+ * tm_cvmx_set - set CMVX registers
+ * @target: The target task.
+ * @regset: The user regset structure.
+ * @pos: The buffer position.
+ * @count: Number of bytes to copy.
+ * @kbuf: Kernel buffer to copy into.
+ * @ubuf: User buffer to copy from.
+ *
+ * This function sets in transaction checkpointed VMX registers.
+ *
+ * When the transaction is active 'vr_state' and 'vr_save' hold
+ * the checkpointed values for the current transaction to fall
+ * back on if it aborts in between. The userspace interface buffer
+ * layout is as follows.
+ *
+ * struct data {
+ * vector128 vr[32];
+ * vector128 vscr;
+ * vector128 vrsave;
+ *};
+ */
+static int tm_cvmx_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int ret;
+
+ BUILD_BUG_ON(TVSO(vscr) != TVSO(vr[32]));
+
+ if (!cpu_has_feature(CPU_FTR_TM))
+ return -ENODEV;
+
+ if (!MSR_TM_ACTIVE(target->thread.regs->msr))
+ return -ENODATA;
+
+ flush_fp_to_thread(target);
+ flush_altivec_to_thread(target);
+ flush_tmregs_to_thread(target);
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ &target->thread.ckvr_state, 0,
+ 33 * sizeof(vector128));
+ if (!ret && count > 0) {
+ /*
+ * We use only the low-order word of vrsave.
+ */
+ union {
+ elf_vrreg_t reg;
+ u32 word;
+ } vrsave;
+ memset(&vrsave, 0, sizeof(vrsave));
+ vrsave.word = target->thread.ckvrsave;
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
+ 33 * sizeof(vector128), -1);
+ if (!ret)
+ target->thread.vrsave = vrsave.word;
+ }
+
+ return ret;
+}
#endif

/*
@@ -934,6 +1081,7 @@ enum powerpc_regset {
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
REGSET_TM_CGPR, /* TM checkpointed GPR registers */
REGSET_TM_CFPR, /* TM checkpointed FPR registers */
+ REGSET_TM_CVMX, /* TM checkpointed VMX registers */
#endif
};

@@ -980,6 +1128,11 @@ static const struct user_regset native_regsets[] = {
.size = sizeof(double), .align = sizeof(double),
.active = tm_cfpr_active, .get = tm_cfpr_get, .set = tm_cfpr_set
},
+ [REGSET_TM_CVMX] = {
+ .core_note_type = NT_PPC_TM_CVMX, .n = ELF_NVMX,
+ .size = sizeof(vector128), .align = sizeof(vector128),
+ .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
+ },
#endif
};

@@ -1217,6 +1370,11 @@ static const struct user_regset compat_regsets[] = {
.size = sizeof(double), .align = sizeof(double),
.active = tm_cfpr_active, .get = tm_cfpr_get, .set = tm_cfpr_set
},
+ [REGSET_TM_CVMX] = {
+ .core_note_type = NT_PPC_TM_CVMX, .n = ELF_NVMX,
+ .size = sizeof(vector128), .align = sizeof(vector128),
+ .active = tm_cvmx_active, .get = tm_cvmx_get, .set = tm_cvmx_set
+ },
#endif
};

--
1.8.3.1