Export the eflags field from the elf header. This allows better

discrimination between different subarch binaries, at least for mips
and arm. Arm is implemented, mips is still tbd, so not currently
exported. aarch64 does not export this because aarch64 binaries use
different tags and flags than arm.

Differential Revision: https://reviews.freebsd.org/D2611

3 files changed, 28 insertions, 22 deletions

diff --git a/sys/arm/include/elf.h b/sys/arm/include/elf.h
index abe7b47..9262682 100644
--- a/sys/arm/include/elf.h
+++ b/sys/arm/include/elf.h
@@ -63,21 +63,21 @@ __ElfType(Auxinfo);
  */
 
 /* Values for a_type. */
-#define AT_NULL         0       /* Terminates the vector. */
-#define AT_IGNORE       1       /* Ignored entry. */
-#define AT_EXECFD       2       /* File descriptor of program to load. */
-#define AT_PHDR         3       /* Program header of program already loaded. */
-#define AT_PHENT        4       /* Size of each program header entry. */
-#define AT_PHNUM        5       /* Number of program header entries. */
-#define AT_PAGESZ       6       /* Page size in bytes. */
-#define AT_BASE         7       /* Interpreter's base address. */
-#define AT_FLAGS        8       /* Flags (unused). */
-#define AT_ENTRY        9       /* Where interpreter should transfer control. */
-#define AT_NOTELF       10      /* Program is not ELF ?? */
-#define AT_UID          11      /* Real uid. */
-#define AT_EUID         12      /* Effective uid. */
-#define AT_GID          13      /* Real gid. */
-#define AT_EGID         14      /* Effective gid. */
+#define	AT_NULL		0	/* Terminates the vector. */
+#define	AT_IGNORE	1	/* Ignored entry. */
+#define	AT_EXECFD	2	/* File descriptor of program to load. */
+#define	AT_PHDR		3	/* Program header of program already loaded. */
+#define	AT_PHENT	4	/* Size of each program header entry. */
+#define	AT_PHNUM	5	/* Number of program header entries. */
+#define	AT_PAGESZ	6	/* Page size in bytes. */
+#define	AT_BASE		7	/* Interpreter's base address. */
+#define	AT_FLAGS	8	/* Flags (unused). */
+#define	AT_ENTRY	9	/* Where interpreter should transfer control. */
+#define	AT_NOTELF	10	/* Program is not ELF ?? */
+#define	AT_UID		11	/* Real uid. */
+#define	AT_EUID		12	/* Effective uid. */
+#define	AT_GID		13	/* Real gid. */
+#define	AT_EGID		14	/* Effective gid. */
 #define	AT_EXECPATH	15	/* Path to the executable. */
 #define	AT_CANARY	16	/* Canary for SSP */
 #define	AT_CANARYLEN	17	/* Length of the canary. */
@@ -87,10 +87,11 @@ __ElfType(Auxinfo);
 #define	AT_PAGESIZESLEN	21	/* Number of pagesizes. */
 #define	AT_TIMEKEEP	22	/* Pointer to timehands. */
 #define	AT_STACKPROT	23	/* Initial stack protection. */
+#define	AT_EHDRFLAGS	24	/* e_flags field from elf hdr */
 
-#define AT_COUNT        24      /* Count of defined aux entry types. */
+#define	AT_COUNT	25	/* Count of defined aux entry types. */
 
-#define	R_ARM_COUNT		33	/* Count of defined relocation types. */
+#define	R_ARM_COUNT	33	/* Count of defined relocation types. */
 
 
 /* Define "machine" characteristics */
@@ -104,16 +105,16 @@ __ElfType(Auxinfo);
 #define	ELF_TARG_VER	1
 
 /* Defines specific for arm headers */
-#define EF_ARM_EABI_VERSION(x) (((x) & EF_ARM_EABIMASK) >> 24)
-#define EF_ARM_EABI_VERSION_UNKNOWN 0
-#define EF_ARM_EABI_FREEBSD_MIN 4
+#define	EF_ARM_EABI_VERSION(x) (((x) & EF_ARM_EABIMASK) >> 24)
+#define	EF_ARM_EABI_VERSION_UNKNOWN 0
+#define	EF_ARM_EABI_FREEBSD_MIN 4
 
 /*
  * Magic number for the elf trampoline, chosen wisely to be an immediate
  * value.
  */
-#define MAGIC_TRAMP_NUMBER	0x5c000003
+#define	MAGIC_TRAMP_NUMBER	0x5c000003
 
-#define	ET_DYN_LOAD_ADDR 0x12000
+#define	ET_DYN_LOAD_ADDR	0x12000
 
 #endif /* !_MACHINE_ELF_H_ */
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 3ff3440..ca0048a 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -972,6 +972,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 	elf_auxargs->base = addr;
 	elf_auxargs->flags = 0;
 	elf_auxargs->entry = entry;
+	elf_auxargs->hdr_eflags = hdr->e_flags;
 
 	imgp->auxargs = elf_auxargs;
 	imgp->interpreted = 0;
@@ -1002,6 +1003,9 @@ __elfN(freebsd_fixup)(register_t **stack_base, struct image_params *imgp)
 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
+#ifdef AT_EHDREFLAGS
+	AUXARGS_ENTRY(pos, AT_EHDRFLAGS, args->hdr_eflags);
+#endif
 	if (imgp->execpathp != 0)
 		AUXARGS_ENTRY(pos, AT_EXECPATH, imgp->execpathp);
 	AUXARGS_ENTRY(pos, AT_OSRELDATE,
diff --git a/sys/sys/imgact_elf.h b/sys/sys/imgact_elf.h
index e8d5567..d1d4f21 100644
--- a/sys/sys/imgact_elf.h
+++ b/sys/sys/imgact_elf.h
@@ -52,6 +52,7 @@ typedef struct {
 	Elf_Size	base;
 	Elf_Size	flags;
 	Elf_Size	entry;
+	Elf_Word	hdr_eflags;		/* e_flags field from ehdr */
 } __ElfN(Auxargs);
 
 typedef struct {