[Qemu-devel] [PATCH] linux-user/FLAT: allow targets to override FLAT reloc processing

[Mike Frysinger <vapier@gentoo.org>]

This brings flatload.c more in line with the current Linux FLAT loader
which allows targets to handle FLAT relocations in their own way.  For
the common behavior, the new functions get stubbed out.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
Note: i'd like to say these changes didn't break existing FLAT targets, but
i'm unable to verify that since all the FLAT targets i tested are already
broken (give me "reloc outside program" errors) ... i was able to verify
that existing behavior seemed to be unchanged though (same # of relocs
were processed with the same result).

 Makefile.target          |    2 +-
 linux-user/flatload.c    |   21 +++++++++------------
 linux-user/target_flat.h |    9 +++++++++
 3 files changed, 19 insertions(+), 13 deletions(-)
 create mode 100644 linux-user/target_flat.h

diff --git a/Makefile.target b/Makefile.target
index 0f0b7a0..6b9a52f 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -321,7 +321,7 @@ ifndef TARGET_ABI_DIR
   TARGET_ABI_DIR=$(TARGET_ARCH)
 endif
 VPATH+=:$(SRC_PATH)/linux-user:$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR)
-CPPFLAGS+=-I$(SRC_PATH)/linux-user -I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR)
+CPPFLAGS+=-I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR) -I$(SRC_PATH)/linux-user
 
 ifdef CONFIG_STATIC
 LDFLAGS+=-static
diff --git a/linux-user/flatload.c b/linux-user/flatload.c
index 543afeb..e63feb4 100644
--- a/linux-user/flatload.c
+++ b/linux-user/flatload.c
@@ -42,6 +42,8 @@
 
 #include "qemu.h"
 #include "flat.h"
+#define ntohl(x) be32_to_cpu(x)
+#include <target_flat.h>
 
 #define DEBUG
 
@@ -51,14 +53,6 @@
 #define	DBG_FLT(a...)
 #endif
 
-#define flat_reloc_valid(reloc, size)             ((reloc) <= (size))
-#define flat_old_ram_flag(flag)                   (flag)
-#ifdef TARGET_WORDS_BIGENDIAN
-#define flat_get_relocate_addr(relval)            (relval)
-#else
-#define flat_get_relocate_addr(relval)            bswap32(relval)
-#endif
-
 #define RELOC_FAILED 0xff00ff01		/* Relocation incorrect somewhere */
 #define UNLOADED_LIB 0x7ff000ff		/* Placeholder for unused library */
 
@@ -79,8 +73,6 @@ static int load_flat_shared_library(int id, struct lib_info *p);
 
 struct linux_binprm;
 
-#define ntohl(x) be32_to_cpu(x)
-
 /****************************************************************************/
 /*
  * create_flat_tables() parses the env- and arg-strings in new user
@@ -339,7 +331,7 @@ failed:
 void old_reloc(struct lib_info *libinfo, uint32_t rl)
 {
 #ifdef DEBUG
-	char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
+	const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 #endif
 	uint32_t *ptr;
         uint32_t offset;
@@ -625,6 +617,7 @@ static int load_flat_file(struct linux_binprm * bprm,
      * __start to address 4 so that is okay).
      */
     if (rev > OLD_FLAT_VERSION) {
+        abi_ulong persistent = 0;
         for (i = 0; i < relocs; i++) {
             abi_ulong addr, relval;
 
@@ -633,6 +626,9 @@ static int load_flat_file(struct linux_binprm * bprm,
                relocated first).  */
             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
                 return -EFAULT;
+            relval = ntohl(relval);
+            if (flat_set_persistent(relval, &persistent))
+                continue;
             addr = flat_get_relocate_addr(relval);
             rp = calc_reloc(addr, libinfo, id, 1);
             if (rp == RELOC_FAILED)
@@ -641,6 +637,7 @@ static int load_flat_file(struct linux_binprm * bprm,
             /* Get the pointer's value.  */
             if (get_user_ual(addr, rp))
                 return -EFAULT;
+            addr = flat_get_addr_from_rp(rp, relval, flags, &persistent);
             if (addr != 0) {
                 /*
                  * Do the relocation.  PIC relocs in the data section are
@@ -656,7 +653,7 @@ static int load_flat_file(struct linux_binprm * bprm,
                     return -ENOEXEC;
 
                 /* Write back the relocated pointer.  */
-                if (put_user_ual(addr, rp))
+                if (flat_put_addr_at_rp(rp, addr, relval))
                     return -EFAULT;
             }
         }
diff --git a/linux-user/target_flat.h b/linux-user/target_flat.h
new file mode 100644
index 0000000..332b6e3
--- /dev/null
+++ b/linux-user/target_flat.h
@@ -0,0 +1,9 @@
+/* If your arch needs to do custom stuff, create your own target_flat.h
+ * header file in linux-user/<your arch>/
+ */
+#define flat_reloc_valid(reloc, size)                        ((reloc) <= (size))
+#define flat_old_ram_flag(flag)                              (flag)
+#define flat_get_relocate_addr(relval)                       (relval)
+#define flat_get_addr_from_rp(rp, relval, flags, persistent) (rp)
+#define flat_set_persistent(relval, persistent)              (*persistent)
+#define flat_put_addr_at_rp(rp, addr, relval)                put_user_ual(addr, rp)
-- 
1.6.0.2