dtrace: fix retrieval of arg5 through arg9

Fix the retrieval of arguments passed on the stack for SDT, USDT, and direct
call probes.  This commit also adds trivial support for testcases related to
this fix.

Orabug: 17368166

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>

diff --git a/dtrace/dt_test_dev.c b/dtrace/dt_test_dev.c
index c0c9abe4c42107939285ef3707971da8022b3f91..2a5f82973ea830b0f9088af85ecd175ae0eb195f 100644 (file)
--- a/dtrace/dt_test_dev.c
+++ b/dtrace/dt_test_dev.c
@@ -65,8 +65,19 @@ void dt_test_destroy(void *arg, dtrace_id_t id, void *parg)
 static long dt_test_ioctl(struct file *file,
                         unsigned int cmd, unsigned long arg)
 {
+       /*
+        * Yes, this is not nice.
+        * Not at all.
+        * But we're doing it anyway...
+        */
+       void (*dt_test_probe)(dtrace_id_t, uintptr_t, uintptr_t, uintptr_t,
+                             uintptr_t, uintptr_t, uintptr_t, uintptr_t,
+                             uintptr_t, uintptr_t, uintptr_t);
+
        if (enabled) {
-               dtrace_probe(pid, cmd, arg, 2, 3, 4);
+               dt_test_probe = (void *)&dtrace_probe;
+               dt_test_probe(pid, cmd, arg, 2ULL, 3ULL, 4ULL, 5ULL,
+                                            6ULL, 7ULL, 8ULL, 9ULL);
 
                return 0;
        }

diff --git a/dtrace/dtrace_dif.c b/dtrace/dtrace_dif.c
index c1d56a2b154bf23efaf823fb5a899fd600d09f48..cd30f6fed80b2db0df8158848e28f3449d7e7aef 100644 (file)
--- a/dtrace/dtrace_dif.c
+++ b/dtrace/dtrace_dif.c
@@ -1985,7 +1985,7 @@ static uint64_t dtrace_dif_variable(dtrace_mstate_t *mstate,
                if (ndx >=
                    sizeof(mstate->dtms_arg) / sizeof(mstate->dtms_arg[0])) {
                        int                     aframes =
-                                       mstate->dtms_probe->dtpr_aframes + 2;
+                                       mstate->dtms_probe->dtpr_aframes + 3;
                        dtrace_provider_t       *pv;
                        uint64_t                val;
 
@@ -2070,7 +2070,7 @@ static uint64_t dtrace_dif_variable(dtrace_mstate_t *mstate,
                if (!dtrace_priv_kernel(state))
                        return 0;
                if (!(mstate->dtms_present & DTRACE_MSTATE_STACKDEPTH)) {
-                       int     aframes = mstate->dtms_probe->dtpr_aframes + 2;
+                       int     aframes = mstate->dtms_probe->dtpr_aframes + 3;
 
                        mstate->dtms_stackdepth = dtrace_getstackdepth(aframes);
                        mstate->dtms_present |= DTRACE_MSTATE_STACKDEPTH;
@@ -2106,7 +2106,7 @@ static uint64_t dtrace_dif_variable(dtrace_mstate_t *mstate,
                        return 0;
 
                if (!(mstate->dtms_present & DTRACE_MSTATE_CALLER)) {
-                       int     aframes = mstate->dtms_probe->dtpr_aframes + 2;
+                       int     aframes = mstate->dtms_probe->dtpr_aframes + 3;
 
                        if (!DTRACE_ANCHORED(mstate->dtms_probe)) {
                                /*

diff --git a/dtrace/dtrace_isa.c b/dtrace/dtrace_isa.c
index 698904f9faa9900e5e1d42270d5feeb2e248f656..189d170581697adb3c57336b2e6d1e3bf21f7c3e 100644 (file)
--- a/dtrace/dtrace_isa.c
+++ b/dtrace/dtrace_isa.c
@@ -114,66 +114,35 @@ DTRACE_FUWORD(16)
 DTRACE_FUWORD(32)
 DTRACE_FUWORD(64)
 
-struct frame {
-       struct frame    *fr_savfp;
-       unsigned long   fr_savpc;
-} __attribute__((packed));
-
-static void dtrace_invop_callsite(void)
+uint64_t dtrace_getarg(int argno, int aframes)
 {
-}
-
-uint64_t dtrace_getarg(int arg, int aframes)
-{
-       struct frame    *fp = (struct frame *)dtrace_getfp();
-       uintptr_t       *stack;
-       int             i;
+       unsigned long   bp;
+       uint64_t        *st;
        uint64_t        val;
-       int             regmap[] = {
-                                       REG_RDI,
-                                       REG_RSI,
-                                       REG_RDX,
-                                       REG_RCX,
-                                       REG_R8,
-                                       REG_R9
-                                  };
-       int             nreg = sizeof(regmap) / sizeof(regmap[0]) - 1;
-
-       for (i = 1; i <= aframes; i++) {
-               fp = fp->fr_savfp;
-
-               if (fp->fr_savpc == (uintptr_t)dtrace_invop_callsite) {
-                       /* FIXME */
-
-                       goto load;
-               }
-       }
-
-       /*
-        * We know that we did not get here through a trap to get into the
-        * dtrace_probe() function, so this was a straight call into it from
-        * a provider.  In that case, we need to shift the argument that we
-        * are looking for, because the probe ID will be the first argument to
-        * dtrace_probe().
-        */
-       arg++;
+       int             i;
 
-       if (arg <= nreg) {
-               /*
-                * This should not happen.  If the argument was passed in a
-                * register then it should have been, ...passed in a register.
-                */
-               DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
-               return 0;
-       }
+       asm volatile("movq %%rbp,%0" : "=m"(bp));
 
-       arg -= nreg + 1;
+       for (i = 0; i < aframes; i++)
+               bp = *((unsigned long *)bp);
 
-       stack = (uintptr_t *)&fp[1];
+       ASSERT(argno >= 5);
 
-load:
+       /*
+        * The first 5 arguments (arg0 through arg4) are passed in registers
+        * to dtrace_probe().  The remaining arguments (arg5 through arg9) are
+        * passed on the stack.
+        *
+        * Stack layout:
+        * bp[0] = pushed bp from caller
+        * bp[1] = return address
+        * bp[2] = 6th argument (arg5 -> argno = 5)
+        * bp[3] = 7th argument (arg6 -> argno = 6)
+        * ...
+        */
        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-       val = stack[arg];
+       st = (uint64_t *)bp;
+       val = st[2 + (argno - 5)];
        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 
        return val;

diff --git a/dtrace/fasttrap_dev.c b/dtrace/fasttrap_dev.c
index 5355d811c77ac8ec83275251b8a1598a02798a4e..833685f6f90813790ddba909042179ab1f5f55bd 100644 (file)
--- a/dtrace/fasttrap_dev.c
+++ b/dtrace/fasttrap_dev.c
@@ -121,6 +121,8 @@ static int fasttrap_pid_probe(fasttrap_machtp_t *mtp, struct pt_regs *regs) {
        if (atomic64_read(&tp->ftt_proc->ftpc_acount) == 0)
                return 0;
 
+       this_cpu_core->cpu_dtrace_regs = regs;
+
        for (id = tp->ftt_ids; id != NULL; id = id->fti_next) {
                fasttrap_probe_t        *ftp = id->fti_probe;
 
@@ -139,6 +141,8 @@ static int fasttrap_pid_probe(fasttrap_machtp_t *mtp, struct pt_regs *regs) {
                }
        }
 
+       this_cpu_core->cpu_dtrace_regs = NULL;
+
        if (is_enabled)
                regs->ax = 1;
 
@@ -703,7 +707,37 @@ static void fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg,
 static uint64_t fasttrap_usdt_getarg(void *arg, dtrace_id_t id, void *parg,
                                     int argno, int aframes)
 {
-       return 0;       /* FIXME */
+       struct pt_regs  *regs = this_cpu_core->cpu_dtrace_regs;
+       uint64_t        *st;
+       uint64_t        val;
+
+       if (regs == NULL)
+               return 0;
+
+       switch (argno) {
+       case 0:
+               return regs->di;
+       case 1:
+               return regs->si;
+       case 2:
+               return regs->dx;
+       case 3:
+               return regs->cx;
+       case 4:
+               return regs->r8;
+       case 5:
+               return regs->r9;
+       }
+
+       ASSERT(argno > 5);
+
+       st = (uint64_t *)regs->sp;
+       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
+       __copy_from_user_inatomic_nocache(&val, (void *)&st[argno - 6],
+                                         sizeof(st[0]));
+       DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
+
+       return val;
 }
 
 static void fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg)

diff --git a/dtrace/sdt_dev.c b/dtrace/sdt_dev.c
index 44684b42e4752b57711dfbd4359447ab37d54aa9..4868db390505a919b4b85da58eb24701531259c3 100644 (file)
--- a/dtrace/sdt_dev.c
+++ b/dtrace/sdt_dev.c
@@ -29,6 +29,7 @@
 #include <linux/miscdevice.h>
 #include <linux/sdt.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include "dtrace.h"
 #include "dtrace_dev.h"
@@ -108,8 +109,13 @@ static uint8_t sdt_invop(struct pt_regs *regs)
 
        for (; sdt != NULL; sdt = sdt->sdp_hashnext) {
                if ((uintptr_t)sdt->sdp_patchpoint == regs->ip) {
+                       this_cpu_core->cpu_dtrace_regs = regs;
+
                        dtrace_probe(sdt->sdp_id, regs->di, regs->si,
                                     regs->dx, regs->cx, regs->r8);
+
+                       this_cpu_core->cpu_dtrace_regs = NULL;
+
                        return DTRACE_INVOP_NOP;
                }
        }
@@ -267,7 +273,37 @@ void sdt_getargdesc(void *arg, dtrace_id_t id, void *parg,
 uint64_t sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno,
                    int aframes)
 {
-       return 0;
+       struct pt_regs  *regs = this_cpu_core->cpu_dtrace_regs;
+       uint64_t        *st;
+       uint64_t        val;
+
+       if (regs == NULL)
+               return 0;
+
+       switch (argno) {
+       case 0:
+               return regs->di;
+       case 1:
+               return regs->si;
+       case 2:
+               return regs->dx;
+       case 3:
+               return regs->cx;
+       case 4:
+               return regs->r8;
+       case 5:
+               return regs->r9;
+       }
+
+       ASSERT(argno > 5);
+
+       st = (uint64_t *)regs->sp;
+       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
+       __copy_from_user_inatomic_nocache(&val, (void *)&st[argno - 6],
+                                         sizeof(st[0]));
+       DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
+
+       return val;
 }
 
 void sdt_destroy(void *arg, dtrace_id_t id, void *parg)

diff --git a/dtrace/sdt_mod.c b/dtrace/sdt_mod.c
index accf402f14f76193bd36dc9ded7b71c06536d41b..643b1539929f16f7137cf95146c4e91da6a7f66e 100644 (file)
--- a/dtrace/sdt_mod.c
+++ b/dtrace/sdt_mod.c
@@ -119,7 +119,7 @@ static dtrace_pops_t sdt_pops = {
        NULL,
        NULL,
        sdt_getargdesc,
-       NULL /* sdt_getarg */,
+       sdt_getarg,
        NULL,
        sdt_destroy,
 };