Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu

Pull m68nommu updates from Greg Ungerer:
 "A series of cleanups for the FLAT format binary loader, binfmt_flat,
  from Christoph.

  The end goal is to support no-MMU on RISC-V, and the last patch
  enables that"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  riscv: add binfmt_flat support
  binfmt_flat: don't offset the data start
  binfmt_flat: move the MAX_SHARED_LIBS definition to binfmt_flat.c
  binfmt_flat: remove the persistent argument from flat_get_addr_from_rp
  binfmt_flat: provide an asm-generic/flat.h
  binfmt_flat: make support for old format binaries optional
  binfmt_flat: add a ARCH_HAS_BINFMT_FLAT option
  binfmt_flat: add endianess annotations
  binfmt_flat: use fixed size type for the on-disk format
  binfmt_flat: consolidate two version of flat_v2_reloc_t
  binfmt_flat: remove the unused OLD_FLAT_FLAG_RAM definition
  binfmt_flat: remove the uapi <linux/flat.h> header
  binfmt_flat: replace flat_argvp_envp_on_stack with a Kconfig variable
  binfmt_flat: remove flat_old_ram_flag
  binfmt_flat: provide a default version of flat_get_relocate_addr
  binfmt_flat: remove flat_set_persistent
  binfmt_flat: remove flat_reloc_valid

2 files changed, 79 insertions, 38 deletions

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index f87ddd1b6d72..62dc4f577ba1 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -91,12 +91,28 @@ config BINFMT_SCRIPT
 
 	  Most systems will not boot if you say M or N here.  If unsure, say Y.
 
+config ARCH_HAS_BINFMT_FLAT
+	bool
+
 config BINFMT_FLAT
 	bool "Kernel support for flat binaries"
-	depends on !MMU || ARM || M68K
+	depends on ARCH_HAS_BINFMT_FLAT
 	help
 	  Support uClinux FLAT format binaries.
 
+config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
+	bool
+
+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 e4b59e76afb0..8c6b50f34466 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -42,6 +42,11 @@
 #include <asm/unaligned.h>
 #include <asm/cacheflush.h>
 #include <asm/page.h>
+#include <asm/flat.h>
+
+#ifndef flat_get_relocate_addr
+#define flat_get_relocate_addr(rel)	(rel)
+#endif
 
 /****************************************************************************/
 
@@ -63,6 +68,12 @@
 #define RELOC_FAILED 0xff00ff01		/* Relocation incorrect somewhere */
 #define UNLOADED_LIB 0x7ff000ff		/* Placeholder for unused library */
 
+#ifdef CONFIG_BINFMT_SHARED_FLAT
+#define	MAX_SHARED_LIBS			(4)
+#else
+#define	MAX_SHARED_LIBS			(1)
+#endif
+
 struct lib_info {
 	struct {
 		unsigned long start_code;		/* Start of text segment */
@@ -120,14 +131,15 @@ static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start
 
 	sp -= bprm->envc + 1;
 	sp -= bprm->argc + 1;
-	sp -= flat_argvp_envp_on_stack() ? 2 : 0;
+	if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
+		sp -= 2; /* argvp + envp */
 	sp -= 1;  /* &argc */
 
 	current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
 	sp = (unsigned long __user *)current->mm->start_stack;
 
 	__put_user(bprm->argc, sp++);
-	if (flat_argvp_envp_on_stack()) {
+	if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
 		unsigned long argv, envp;
 		argv = (unsigned long)(sp + 2);
 		envp = (unsigned long)(sp + 2 + bprm->argc + 1);
@@ -345,7 +357,7 @@ calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
 	start_code = p->lib_list[id].start_code;
 	text_len = p->lib_list[id].text_len;
 
-	if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
+	if (r > start_brk - start_data + text_len) {
 		pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
 		       r, start_brk-start_data+text_len, text_len);
 		goto failed;
@@ -368,6 +380,7 @@ failed:
 
 /****************************************************************************/
 
+#ifdef CONFIG_BINFMT_FLAT_OLD
 static void old_reloc(unsigned long rl)
 {
 	static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
@@ -405,6 +418,7 @@ static void old_reloc(unsigned long rl)
 
 	pr_debug("Relocation became %lx\n", val);
 }
+#endif /* CONFIG_BINFMT_FLAT_OLD */
 
 /****************************************************************************/
 
@@ -415,7 +429,8 @@ static int load_flat_file(struct linux_binprm *bprm,
 	unsigned long textpos, datapos, realdatastart;
 	u32 text_len, data_len, bss_len, stack_len, full_data, flags;
 	unsigned long len, memp, memp_size, extra, rlim;
-	u32 __user *reloc, *rp;
+	__be32 __user *reloc;
+	u32 __user *rp;
 	struct inode *inode;
 	int i, rev, relocs;
 	loff_t fpos;
@@ -454,6 +469,7 @@ 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);
@@ -470,6 +486,23 @@ static int load_flat_file(struct linux_binprm *bprm,
 	}
 
 	/*
+	 * 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.
 	 * If some top bits are set we have probable binary corruption.
@@ -480,13 +513,6 @@ 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 && flat_old_ram_flag(flags))
-		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");
@@ -547,7 +573,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 			goto err;
 		}
 
-		len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
+		len = data_len + extra;
 		len = PAGE_ALIGN(len);
 		realdatastart = vm_mmap(NULL, 0, len,
 			PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
@@ -561,9 +587,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 			vm_munmap(textpos, text_len);
 			goto err;
 		}
-		datapos = ALIGN(realdatastart +
-				MAX_SHARED_LIBS * sizeof(unsigned long),
-				FLAT_DATA_ALIGN);
+		datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN);
 
 		pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
 			 data_len + bss_len + stack_len, datapos);
@@ -587,13 +611,13 @@ static int load_flat_file(struct linux_binprm *bprm,
 			goto err;
 		}
 
-		reloc = (u32 __user *)
+		reloc = (__be32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = realdatastart;
 		memp_size = len;
 	} else {
 
-		len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32);
+		len = text_len + data_len + extra;
 		len = PAGE_ALIGN(len);
 		textpos = vm_mmap(NULL, 0, len,
 			PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
@@ -608,11 +632,9 @@ static int load_flat_file(struct linux_binprm *bprm,
 		}
 
 		realdatastart = textpos + ntohl(hdr->data_start);
-		datapos = ALIGN(realdatastart +
-				MAX_SHARED_LIBS * sizeof(u32),
-				FLAT_DATA_ALIGN);
+		datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN);
 
-		reloc = (u32 __user *)
+		reloc = (__be32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = textpos;
 		memp_size = len;
@@ -627,8 +649,9 @@ static int load_flat_file(struct linux_binprm *bprm,
 					 (text_len + full_data
 						  - sizeof(struct flat_hdr)),
 					 0);
-			memmove((void *) datapos, (void *) realdatastart,
-					full_data);
+			if (datapos != realdatastart)
+				memmove((void *)datapos, (void *)realdatastart,
+						full_data);
 #else
 			/*
 			 * This is used on MMU systems mainly for testing.
@@ -684,8 +707,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 		if (IS_ERR_VALUE(result)) {
 			ret = result;
 			pr_err("Unable to read code+data+bss, errno %d\n", ret);
-			vm_munmap(textpos, text_len + data_len + extra +
-				MAX_SHARED_LIBS * sizeof(u32));
+			vm_munmap(textpos, text_len + data_len + extra);
 			goto err;
 		}
 	}
@@ -775,20 +797,18 @@ static int load_flat_file(struct linux_binprm *bprm,
 	 * __start to address 4 so that is okay).
 	 */
 	if (rev > OLD_FLAT_VERSION) {
-		u32 __maybe_unused persistent = 0;
 		for (i = 0; i < relocs; i++) {
 			u32 addr, relval;
+			__be32 tmp;
 
 			/*
 			 * Get the address of the pointer to be
 			 * relocated (of course, the address has to be
 			 * relocated first).
 			 */
-			if (get_user(relval, reloc + i))
+			if (get_user(tmp, reloc + i))
 				return -EFAULT;
-			relval = ntohl(relval);
-			if (flat_set_persistent(relval, &persistent))
-				continue;
+			relval = ntohl(tmp);
 			addr = flat_get_relocate_addr(relval);
 			rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
 			if (rp == (u32 __user *)RELOC_FAILED) {
@@ -797,8 +817,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 			}
 
 			/* Get the pointer's value.  */
-			ret = flat_get_addr_from_rp(rp, relval, flags,
-							&addr, &persistent);
+			ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
 			if (unlikely(ret))
 				goto err;
 
@@ -807,8 +826,13 @@ static int load_flat_file(struct linux_binprm *bprm,
 				 * Do the relocation.  PIC relocs in the data section are
 				 * already in target order
 				 */
-				if ((flags & FLAT_FLAG_GOTPIC) == 0)
-					addr = ntohl(addr);
+				if ((flags & FLAT_FLAG_GOTPIC) == 0) {
+					/*
+					 * Meh, the same value can have a different
+					 * byte order based on a flag..
+					 */
+					addr = ntohl((__force __be32)addr);
+				}
 				addr = calc_reloc(addr, libinfo, id, 0);
 				if (addr == RELOC_FAILED) {
 					ret = -ENOEXEC;
@@ -821,14 +845,15 @@ static int load_flat_file(struct linux_binprm *bprm,
 					goto err;
 			}
 		}
+#ifdef CONFIG_BINFMT_FLAT_OLD
 	} else {
 		for (i = 0; i < relocs; i++) {
-			u32 relval;
+			__be32 relval;
 			if (get_user(relval, reloc + i))
 				return -EFAULT;
-			relval = ntohl(relval);
-			old_reloc(relval);
+			old_reloc(ntohl(relval));
 		}
+#endif /* CONFIG_BINFMT_FLAT_OLD */
 	}
 
 	flush_icache_range(start_code, end_code);