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From: Christoph Hellwig <hch@lst.de>
To: Greg Ungerer <gerg@linux-m68k.org>
Cc: uclinux-h8-devel@lists.sourceforge.jp,
	linux-xtensa@linux-xtensa.org, Michal Simek <monstr@monstr.eu>,
	linux-c6x-dev@linux-c6x.org, linux-sh@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 12/17] binfmt_flat: make support for old format binaries optional
Date: Thu, 13 Jun 2019 09:08:58 +0200
Message-ID: <20190613070903.17214-13-hch@lst.de> (raw)
In-Reply-To: <20190613070903.17214-1-hch@lst.de>

No need to carry the extra code around, given that systems using flat
binaries are generally very resource constrained.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/Kconfig.binfmt |  7 +++++++
 fs/binfmt_flat.c  | 30 ++++++++++++++++++++++--------
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 286b425b30b9..62dc4f577ba1 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -106,6 +106,13 @@ config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
 config BINFMT_FLAT_OLD_ALWAYS_RAM
 	bool
 
+config BINFMT_FLAT_OLD
+	bool "Enable support for very old legacy flat binaries"
+	depends on BINFMT_FLAT
+	help
+	  Support decade old uClinux FLAT format binaries.  Unless you know
+	  you have some of those say N here.
+
 config BINFMT_ZFLAT
 	bool "Enable ZFLAT support"
 	depends on BINFMT_FLAT
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 404a0bedc85b..1e88f4e62e65 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -374,6 +374,7 @@ calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
 
 /****************************************************************************/
 
+#ifdef CONFIG_BINFMT_FLAT_OLD
 static void old_reloc(unsigned long rl)
 {
 	static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
@@ -411,6 +412,7 @@ static void old_reloc(unsigned long rl)
 
 	pr_debug("Relocation became %lx\n", val);
 }
+#endif /* CONFIG_BINFMT_FLAT_OLD */
 
 /****************************************************************************/
 
@@ -461,6 +463,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 	if (flags & FLAT_FLAG_KTRACE)
 		pr_info("Loading file: %s\n", bprm->filename);
 
+#ifdef CONFIG_BINFMT_FLAT_OLD
 	if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 		pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
 		       rev, FLAT_VERSION, OLD_FLAT_VERSION);
@@ -476,6 +479,23 @@ static int load_flat_file(struct linux_binprm *bprm,
 		goto err;
 	}
 
+	/*
+	 * fix up the flags for the older format,  there were all kinds
+	 * of endian hacks,  this only works for the simple cases
+	 */
+	if (rev == OLD_FLAT_VERSION &&
+	   (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
+		flags = FLAT_FLAG_RAM;
+
+#else /* CONFIG_BINFMT_FLAT_OLD */
+	if (rev != FLAT_VERSION) {
+		pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
+		       rev, FLAT_VERSION);
+		ret = -ENOEXEC;
+		goto err;
+	}
+#endif /* !CONFIG_BINFMT_FLAT_OLD */
+
 	/*
 	 * Make sure the header params are sane.
 	 * 28 bits (256 MB) is way more than reasonable in this case.
@@ -487,14 +507,6 @@ static int load_flat_file(struct linux_binprm *bprm,
 		goto err;
 	}
 
-	/*
-	 * fix up the flags for the older format,  there were all kinds
-	 * of endian hacks,  this only works for the simple cases
-	 */
-	if (rev == OLD_FLAT_VERSION &&
-	   (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
-		flags = FLAT_FLAG_RAM;
-
 #ifndef CONFIG_BINFMT_ZFLAT
 	if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 		pr_err("Support for ZFLAT executables is not enabled.\n");
@@ -833,6 +845,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 					goto err;
 			}
 		}
+#ifdef CONFIG_BINFMT_FLAT_OLD
 	} else {
 		for (i = 0; i < relocs; i++) {
 			__be32 relval;
@@ -840,6 +853,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 				return -EFAULT;
 			old_reloc(ntohl(relval));
 		}
+#endif /* CONFIG_BINFMT_FLAT_OLD */
 	}
 
 	flush_icache_range(start_code, end_code);
-- 
2.20.1


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  parent reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-13  7:08 binfmt_flat cleanups and RISC-V support v2 Christoph Hellwig
2019-06-13  7:08 ` [PATCH 01/17] binfmt_flat: remove flat_reloc_valid Christoph Hellwig
2019-06-13  7:08 ` [PATCH 02/17] binfmt_flat: remove flat_set_persistent Christoph Hellwig
2019-06-13  7:08 ` [PATCH 03/17] binfmt_flat: provide a default version of flat_get_relocate_addr Christoph Hellwig
2019-06-13  7:08 ` [PATCH 04/17] binfmt_flat: remove flat_old_ram_flag Christoph Hellwig
2019-06-13  7:08 ` [PATCH 05/17] binfmt_flat: replace flat_argvp_envp_on_stack with a Kconfig variable Christoph Hellwig
2019-06-13  7:08 ` [PATCH 06/17] binfmt_flat: remove the uapi <linux/flat.h> header Christoph Hellwig
2019-06-13  7:08 ` [PATCH 07/17] binfmt_flat: remove the unused OLD_FLAT_FLAG_RAM definition Christoph Hellwig
2019-06-13  7:08 ` [PATCH 08/17] binfmt_flat: consolidate two version of flat_v2_reloc_t Christoph Hellwig
2019-06-25 22:29   ` Al Viro
2019-06-26  7:23     ` Greg Ungerer
2019-06-26  8:18       ` Geert Uytterhoeven
2019-06-26 12:14         ` Greg Ungerer
2019-06-13  7:08 ` [PATCH 09/17] binfmt_flat: use fixed size type for the on-disk format Christoph Hellwig
2019-06-13  7:08 ` [PATCH 10/17] binfmt_flat: add endianess annotations Christoph Hellwig
2019-06-13  7:08 ` [PATCH 11/17] binfmt_flat: add a ARCH_HAS_BINFMT_FLAT option Christoph Hellwig
2019-06-13  7:08 ` Christoph Hellwig [this message]
2019-06-13  7:08 ` [PATCH 13/17] binfmt_flat: provide an asm-generic/flat.h Christoph Hellwig
2019-06-13  7:09 ` [PATCH 14/17] binfmt_flat: remove the persistent argument from flat_get_addr_from_rp Christoph Hellwig
2019-06-13  7:09 ` [PATCH 15/17] binfmt_flat: move the MAX_SHARED_LIBS definition to binfmt_flat.c Christoph Hellwig
2019-06-14  8:35   ` Sergei Shtylyov
2019-06-13  7:09 ` [PATCH 16/17] binfmt_flat: don't offset the data start Christoph Hellwig
2019-06-13  7:09 ` [PATCH 17/17] riscv: add binfmt_flat support Christoph Hellwig
2019-06-13 23:38 ` binfmt_flat cleanups and RISC-V support v2 Greg Ungerer

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