[PATCH 1/3] um: Create asm/sections.h

[PATCH 1/3] um: Create asm/sections.h

[Nicolas Iooss]

arch/um/kernel/dyn.lds.S and arch/um/kernel/uml.lds.S define some
UML-specific symbols.  These symbols are used in the kernel part of UML
with extern declarations.

Move these declarations to a new header, asm/sections.h, like other
architectures do.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
 arch/um/include/asm/Kbuild     | 1 -
 arch/um/include/asm/sections.h | 9 +++++++++
 arch/um/kernel/physmem.c       | 3 +--
 arch/um/kernel/skas/mmu.c      | 3 +--
 arch/um/kernel/um_arch.c       | 2 --
 5 files changed, 11 insertions(+), 7 deletions(-)
 create mode 100644 arch/um/include/asm/sections.h

diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 244b12c8cb39..21fd5c647442 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -23,7 +23,6 @@ generic-y += pci.h
 generic-y += percpu.h
 generic-y += preempt.h
 generic-y += scatterlist.h
-generic-y += sections.h
 generic-y += switch_to.h
 generic-y += topology.h
 generic-y += trace_clock.h
diff --git a/arch/um/include/asm/sections.h b/arch/um/include/asm/sections.h
new file mode 100644
index 000000000000..3a6ebcc65519
--- /dev/null
+++ b/arch/um/include/asm/sections.h
@@ -0,0 +1,9 @@
+#ifndef __UM_SECTIONS_H
+#define __UM_SECTIONS_H
+
+#include <asm-generic/sections.h>
+
+extern char __binary_start;
+extern int __syscall_stub_start, __syscall_stub_end;
+
+#endif
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 30fdd5d0067b..db05c067665a 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -8,6 +8,7 @@
 #include <linux/mm.h>
 #include <linux/pfn.h>
 #include <asm/page.h>
+#include <asm/sections.h>
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
@@ -75,8 +76,6 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 	}
 }
 
-extern int __syscall_stub_start;
-
 void __init setup_physmem(unsigned long start, unsigned long reserve_end,
 			  unsigned long len, unsigned long long highmem)
 {
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 007d5503f49b..d2a0a4c0cd91 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -8,12 +8,11 @@
 #include <linux/slab.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
+#include <asm/sections.h>
 #include <as-layout.h>
 #include <os.h>
 #include <skas.h>
 
-extern int __syscall_stub_start;
-
 static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
 			 unsigned long kernel)
 {
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 016adf0985d5..02c21f6e0983 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -259,8 +259,6 @@ EXPORT_SYMBOL(end_iomem);
 
 #define MIN_VMALLOC (32 * 1024 * 1024)
 
-extern char __binary_start;
-
 int __init linux_main(int argc, char **argv)
 {
 	unsigned long avail, diff;
-- 
2.1.1

[PATCH 2/3] um: Use char[] for linker script address declarations

[Nicolas Iooss]

The linker script defines some variables which are declared either with
type char[] in include/asm-generic/sections.h or with a meaningless
integer type in arch/um/include/asm/sections.h.

Fix this inconsistency by declaring every variable char[].

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
 arch/um/include/asm/sections.h | 4 ++--
 arch/um/kernel/physmem.c       | 4 ++--
 arch/um/kernel/skas/mmu.c      | 4 ++--
 arch/um/kernel/um_arch.c       | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/um/include/asm/sections.h b/arch/um/include/asm/sections.h
index 3a6ebcc65519..cafcf684d947 100644
--- a/arch/um/include/asm/sections.h
+++ b/arch/um/include/asm/sections.h
@@ -3,7 +3,7 @@
 
 #include <asm-generic/sections.h>
 
-extern char __binary_start;
-extern int __syscall_stub_start, __syscall_stub_end;
+extern char __binary_start[];
+extern char __syscall_stub_start[], __syscall_stub_end[];
 
 #endif
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index db05c067665a..c833a5dec1e7 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -100,8 +100,8 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
 	 * Special kludge - This page will be mapped in to userspace processes
 	 * from physmem_fd, so it needs to be written out there.
 	 */
-	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
-	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
+	os_seek_file(physmem_fd, __pa(__syscall_stub_start));
+	os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE);
 	os_fsync_file(physmem_fd);
 
 	bootmap_size = init_bootmem(pfn, pfn + delta);
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index d2a0a4c0cd91..e40ce29bdc2c 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -108,7 +108,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 		return;
 
 	ret = init_stub_pte(mm, STUB_CODE,
-			    (unsigned long) &__syscall_stub_start);
+			    (unsigned long) __syscall_stub_start);
 	if (ret)
 		goto out;
 
@@ -116,7 +116,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 	if (ret)
 		goto out;
 
-	mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
+	mm->context.stub_pages[0] = virt_to_page(__syscall_stub_start);
 	mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
 
 	/* dup_mmap already holds mmap_sem */
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 02c21f6e0983..5dd632203dca 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -313,7 +313,7 @@ int __init linux_main(int argc, char **argv)
 		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 	}
 
-	uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
+	uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
 
 	/* Reserve up to 4M after the current brk */
 	uml_reserved = ROUND_4M(brk_start) + (1 << 22);
-- 
2.1.1

[PATCH 3/3] um/os-Linux: Use char[] for syscall_stub declarations

[Nicolas Iooss]

When declaring __syscall_stub_start, use the same type in UML userspace
code as in arch/um/include/asm/sections.h.

While at it, also declare batch_syscall_stub as char[].

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
 arch/um/os-Linux/skas/mem.c     |  6 +++---
 arch/um/os-Linux/skas/process.c | 11 +++++------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 689b18db798f..abb02becca80 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -19,7 +19,7 @@
 #include <sysdep/ptrace.h>
 #include <sysdep/stub.h>
 
-extern unsigned long batch_syscall_stub, __syscall_stub_start;
+extern char batch_syscall_stub[], __syscall_stub_start[];
 
 extern void wait_stub_done(int pid);
 
@@ -39,8 +39,8 @@ static int __init init_syscall_regs(void)
 {
 	get_safe_registers(syscall_regs, NULL);
 	syscall_regs[REGS_IP_INDEX] = STUB_CODE +
-		((unsigned long) &batch_syscall_stub -
-		 (unsigned long) &__syscall_stub_start);
+		((unsigned long) batch_syscall_stub -
+		 (unsigned long) __syscall_stub_start);
 	return 0;
 }
 
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 908579f2b0ab..fa934d0c8932 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -193,7 +193,7 @@ static void handle_trap(int pid, struct uml_pt_regs *regs,
 	handle_syscall(regs);
 }
 
-extern int __syscall_stub_start;
+extern char __syscall_stub_start[];
 
 static int userspace_tramp(void *stack)
 {
@@ -218,7 +218,7 @@ static int userspace_tramp(void *stack)
 		 */
 		int fd;
 		unsigned long long offset;
-		fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
+		fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
 		addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
 			      PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
 		if (addr == MAP_FAILED) {
@@ -245,7 +245,7 @@ static int userspace_tramp(void *stack)
 
 		unsigned long v = STUB_CODE +
 				  (unsigned long) stub_segv_handler -
-				  (unsigned long) &__syscall_stub_start;
+				  (unsigned long) __syscall_stub_start;
 
 		set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
 		sigemptyset(&sa.sa_mask);
@@ -474,7 +474,7 @@ static int __init init_thread_regs(void)
 	/* Set parent's instruction pointer to start of clone-stub */
 	thread_regs[REGS_IP_INDEX] = STUB_CODE +
 				(unsigned long) stub_clone_handler -
-				(unsigned long) &__syscall_stub_start;
+				(unsigned long) __syscall_stub_start;
 	thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
 		sizeof(void *);
 #ifdef __SIGNAL_FRAMESIZE
@@ -582,8 +582,7 @@ int map_stub_pages(int fd, unsigned long code, unsigned long data,
 	struct proc_mm_op mmop;
 	int n;
 	unsigned long long code_offset;
-	int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
-				   &code_offset);
+	int code_fd = phys_mapping(to_phys(__syscall_stub_start), &code_offset);
 
 	mmop = ((struct proc_mm_op) { .op        = MM_MMAP,
 				      .u         =
-- 
2.1.1

Re: [PATCH 3/3] um/os-Linux: Use char[] for syscall_stub declarations

[Richard Weinberger]

Am 12.10.2014 um 13:02 schrieb Nicolas Iooss:
> When declaring __syscall_stub_start, use the same type in UML userspace
> code as in arch/um/include/asm/sections.h.
> 
> While at it, also declare batch_syscall_stub as char[].
> 
> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
> ---
>  arch/um/os-Linux/skas/mem.c     |  6 +++---
>  arch/um/os-Linux/skas/process.c | 11 +++++------
>  2 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
> index 689b18db798f..abb02becca80 100644
> --- a/arch/um/os-Linux/skas/mem.c
> +++ b/arch/um/os-Linux/skas/mem.c
> @@ -19,7 +19,7 @@
>  #include <sysdep/ptrace.h>
>  #include <sysdep/stub.h>
>  
> -extern unsigned long batch_syscall_stub, __syscall_stub_start;
> +extern char batch_syscall_stub[], __syscall_stub_start[];
>  
>  extern void wait_stub_done(int pid);
>  
> @@ -39,8 +39,8 @@ static int __init init_syscall_regs(void)
>  {
>  	get_safe_registers(syscall_regs, NULL);
>  	syscall_regs[REGS_IP_INDEX] = STUB_CODE +
> -		((unsigned long) &batch_syscall_stub -
> -		 (unsigned long) &__syscall_stub_start);
> +		((unsigned long) batch_syscall_stub -
> +		 (unsigned long) __syscall_stub_start);
>  	return 0;
>  }
>  
> diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
> index 908579f2b0ab..fa934d0c8932 100644
> --- a/arch/um/os-Linux/skas/process.c
> +++ b/arch/um/os-Linux/skas/process.c
> @@ -193,7 +193,7 @@ static void handle_trap(int pid, struct uml_pt_regs *regs,
>  	handle_syscall(regs);
>  }
>  
> -extern int __syscall_stub_start;
> +extern char __syscall_stub_start[];
>  
>  static int userspace_tramp(void *stack)
>  {
> @@ -218,7 +218,7 @@ static int userspace_tramp(void *stack)
>  		 */
>  		int fd;
>  		unsigned long long offset;
> -		fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
> +		fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
>  		addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
>  			      PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
>  		if (addr == MAP_FAILED) {
> @@ -245,7 +245,7 @@ static int userspace_tramp(void *stack)
>  
>  		unsigned long v = STUB_CODE +
>  				  (unsigned long) stub_segv_handler -
> -				  (unsigned long) &__syscall_stub_start;
> +				  (unsigned long) __syscall_stub_start;
>  
>  		set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
>  		sigemptyset(&sa.sa_mask);
> @@ -474,7 +474,7 @@ static int __init init_thread_regs(void)
>  	/* Set parent's instruction pointer to start of clone-stub */
>  	thread_regs[REGS_IP_INDEX] = STUB_CODE +
>  				(unsigned long) stub_clone_handler -
> -				(unsigned long) &__syscall_stub_start;
> +				(unsigned long) __syscall_stub_start;
>  	thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
>  		sizeof(void *);
>  #ifdef __SIGNAL_FRAMESIZE
> @@ -582,8 +582,7 @@ int map_stub_pages(int fd, unsigned long code, unsigned long data,
>  	struct proc_mm_op mmop;
>  	int n;
>  	unsigned long long code_offset;
> -	int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
> -				   &code_offset);
> +	int code_fd = phys_mapping(to_phys(__syscall_stub_start), &code_offset);
>  
>  	mmop = ((struct proc_mm_op) { .op        = MM_MMAP,
>  				      .u         =

Thank you Nicoals, all three patches are now in my 4.2 queue!
Special thanks to Thomas Meyer for exhuming this patches. :-)

Thanks,
//richard