libsframe: fix issue finding FRE in PCMASK type SFrame FDEs

SFrame FDEs of type SFRAME_FDE_TYPE_PCMASK are used for repetitive code
patterns, e.g., pltN entries.  For SFrame FDEs of type
SFRAME_FDE_TYPE_PCMASK, sframe_fre_check_range_p erroneously tested the
given PC instead of the masked PC offset from function start address.
Therefore it only worked correctly by chance, e.g., if the function start
address was aligned on the repetition block size.

For regular SFrame FDEs the PC offset from function start address must
be within a SFrame FRE's start IP offset and end IP offset.  For SFrame
FDEs of type SFRAME_FDE_TYPE_PCMASK, the masked PC offset must be within
that range.

SFrame FRE start/end IP offsets are relative to the SFrame FDE function
start address. For regular SFrame FDEs, the PC offset from function
start address must be within a SFrame FRE's start IP offset and end IP
offset.  For SFRAME_FDE_TYPE_PCMASK type FDEs, the masked PC offset must
be within that range.

Exercise the testcase for a variety of placements; without the fix some
of these tests will fail.  Also, make the testcase itself easier to
follow by adding appropriate vars where applicable.

libsframe/
	* sframe.c (sframe_fre_check_range_p): Fix logic for
	SFRAME_FDE_TYPE_PCMASK type FDE.
libsframe/testsuite/
	* libsframe.find/plt-findfre-1.c: Adjust the test for a variety
	of placements of .sframe and .plt.

Co-Authored-by: Jens Remus <jremus@linux.ibm.com>

diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index c2693b978ec3992e99540877107db0ba9aa8a512..c1bc692829a9c175101c70eef3b505d322d9bf01 100644 (file)
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -372,40 +372,27 @@ sframe_fre_check_range_p (sframe_func_desc_entry *fdep,
                          int32_t start_ip_offset, int32_t end_ip_offset,
                          int32_t pc)
 {
-  int32_t start_ip, end_ip;
   int32_t func_start_addr;
   uint8_t rep_block_size;
   uint32_t fde_type;
-  int32_t masked_pc;
+  int32_t pc_offset;
   bool mask_p;
-  bool ret;
-
-  ret = false;
 
   if (!fdep)
-    return ret;
+    return false;
 
   func_start_addr = fdep->sfde_func_start_address;
   fde_type = sframe_get_fde_type (fdep);
   mask_p = (fde_type == SFRAME_FDE_TYPE_PCMASK);
   rep_block_size = fdep->sfde_func_rep_size;
 
-  if (!mask_p)
-    {
-      start_ip = start_ip_offset + func_start_addr;
-      end_ip = end_ip_offset + func_start_addr;
-      ret = ((start_ip <= pc) && (end_ip >= pc));
-    }
-  else
-    {
-      /* For FDEs for repetitive pattern of insns, we need to return the FRE
-        where pc % rep_block_size is between start_ip_offset and
-        end_ip_offset.  */
-      masked_pc = pc % rep_block_size;
-      ret = ((start_ip_offset <= masked_pc) && (end_ip_offset >= masked_pc));
-    }
+  pc_offset = pc - func_start_addr;
+  /* For SFrame FDEs encoding information for repetitive pattern of insns,
+     masking with the rep_block_size is necessary to find the matching FRE.  */
+  if (mask_p)
+    pc_offset = pc_offset % rep_block_size;
 
-  return ret;
+  return (start_ip_offset <= pc_offset) && (end_ip_offset >= pc_offset);
 }
 
 static int

diff --git a/libsframe/testsuite/libsframe.find/plt-findfre-1.c b/libsframe/testsuite/libsframe.find/plt-findfre-1.c
index c84b46f4d35f1d7465951a73b06ba93130144f86..60037fd67ea0c01d5dcc575239c52895b32cd70a 100644 (file)
--- a/libsframe/testsuite/libsframe.find/plt-findfre-1.c
+++ b/libsframe/testsuite/libsframe.find/plt-findfre-1.c
@@ -28,12 +28,13 @@
 #include <dejagnu.h>
 
 static int
-add_plt_fde1 (sframe_encoder_ctx *ectx, int idx)
+add_plt_fde1 (sframe_encoder_ctx *ectx, uint32_t plt_vaddr,
+             uint32_t sframe_vaddr, int idx)
 {
-  int i, err;
   /* A contiguous block containing 3 FREs.  The start_ip_offset must remain
      less than 16 bytes.  */
-  sframe_frame_row_entry fres[]
+#define PLT1_NUM_FRES    3
+  sframe_frame_row_entry fres[PLT1_NUM_FRES]
     = { {0x0, {0x1, 0, 0}, 0x3},
        {0x6, {0x2, 0xf0, 0}, 0x5},
        {0xc, {0x3, 0xf0, 0}, 0x4}
@@ -41,19 +42,26 @@ add_plt_fde1 (sframe_encoder_ctx *ectx, int idx)
 
   unsigned char finfo = sframe_fde_create_func_info (SFRAME_FRE_TYPE_ADDR1,
                                                     SFRAME_FDE_TYPE_PCMASK);
+  int32_t func_start_addr = plt_vaddr - sframe_vaddr;
+
   /* 5 pltN entries of 16 bytes each.  */
-  err = sframe_encoder_add_funcdesc_v2 (ectx, 0x1000, 16*5, finfo, 16, 3);
+  int err = sframe_encoder_add_funcdesc_v2 (ectx, func_start_addr,
+                                           16 * 5 /* func size in bytes.  */,
+                                           finfo,
+                                           16 /* rep block size in bytes.  */,
+                                           PLT1_NUM_FRES);
   if (err == -1)
     return err;
 
-  for (i = 0; i < 3; i++)
-    if (sframe_encoder_add_fre (ectx, idx, fres+i) == SFRAME_ERR)
+  for (unsigned i = 0; i < PLT1_NUM_FRES; i++)
+    if (sframe_encoder_add_fre (ectx, idx, fres + i) == SFRAME_ERR)
       return -1;
 
   return 0;
 }
 
-int main (void)
+static
+void test_plt_findfre (uint32_t plt_vaddr, uint32_t sframe_vaddr)
 {
   sframe_encoder_ctx *ectx;
   sframe_decoder_ctx *dctx;
@@ -61,7 +69,7 @@ int main (void)
   char *sframe_buf;
   size_t sf_size;
   int err = 0;
-  unsigned int fde_cnt = 0;
+  uint32_t fde_cnt = 0;
 
 #define TEST(name, cond)                                                      \
   do                                                                          \
@@ -78,7 +86,7 @@ int main (void)
                        -8, /* Fixed RA offset for AMD64.  */
                        &err);
 
-  err = add_plt_fde1 (ectx, 0);
+  err = add_plt_fde1 (ectx, plt_vaddr, sframe_vaddr, 0);
   TEST ("plt-findfre-1: Adding FDE1 for plt", err == 0);
 
   fde_cnt = sframe_encoder_get_num_fidx (ectx);
@@ -88,40 +96,53 @@ int main (void)
   TEST ("plt-findfre-1: Encoder write", err == 0);
 
   dctx = sframe_decode (sframe_buf, sf_size, &err);
-  TEST("plt-findfre-1: Decoder setup", dctx != NULL);
+  TEST ("plt-findfre-1: Decoder setup", dctx != NULL);
 
   /* Find the first FRE in PLT1.  */
-  err = sframe_find_fre (dctx, (0x1000 + 0x0), &frep);
-  TEST("plt-findfre-1: Find first FRE in PLT1",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x1)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 0x0 - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find first FRE in PLT1",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x1));
 
   /* Find the second FRE.  */
-  err = sframe_find_fre (dctx, (0x1000 + 0x6), &frep);
-  TEST("plt-findfre-1: Find second FRE in PLT1",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x2)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 0x6 - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find second FRE in PLT1",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x2));
 
   /* Find the last FRE.  */
-  err = sframe_find_fre (dctx, (0x1000 + 0xc), &frep);
-  TEST("plt-findfre-1: Find last FRE in PLT1",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x3)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 0xc - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find last FRE in PLT1",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x3));
 
   /* Find the first FRE in PLT4.  */
-  err = sframe_find_fre (dctx, (0x1000 + 16*3 + 0x0), &frep);
-  TEST("plt-findfre-1: Find first FRE in PLT4",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x1)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 16*3 + 0x0 - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find first FRE in PLT4",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x1));
 
   /* Find the second FRE in PLT4.  */
-  err = sframe_find_fre (dctx, (0x1000 + 16*3 + 0x6), &frep);
-  TEST("plt-findfre-1: Find second FRE in PLT4",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x2)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 16*3 + 0x6 - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find second FRE in PLT4",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x2));
 
   /* Find the last FRE in PLT4.  */
-  err = sframe_find_fre (dctx, (0x1000 + 16*3 + 0xc), &frep);
-  TEST("plt-findfre-1: Find last FRE in PLT4",
-       ((err == 0) && (sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x3)));
+  err = sframe_find_fre (dctx, (plt_vaddr + 16*3 + 0xc - sframe_vaddr), &frep);
+  TEST ("plt-findfre-1: Find last FRE in PLT4",
+       (err == 0 && sframe_fre_get_cfa_offset (dctx, &frep, &err) == 0x3));
 
   sframe_encoder_free (&ectx);
   sframe_decoder_free (&dctx);
+}
 
-  return 0;
+int main (void)
+{
+  uint32_t sframe_vaddr = 0x402220;
+  uint32_t plt_vaddr = 0x401020;
+  printf ("Testing with plt_vaddr = %#x; sframe_vaddr = %#x\n", plt_vaddr,
+         sframe_vaddr);
+  test_plt_findfre (plt_vaddr, sframe_vaddr);
+
+  sframe_vaddr = 0x401020;
+  plt_vaddr = 0x402220;
+  printf ("Testing with plt_vaddr = %#x; sframe_vaddr = %#x\n", plt_vaddr,
+         sframe_vaddr);
+  test_plt_findfre (plt_vaddr, sframe_vaddr);
 }