* [PATCH] Xen i386 xen-head.S fix sections mixup
@ 2007-08-20 3:04 Mathieu Desnoyers
2007-08-20 6:13 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 5+ messages in thread
From: Mathieu Desnoyers @ 2007-08-20 3:04 UTC (permalink / raw)
To: Andrew Morton, jeremy, chrisw; +Cc: virtualization, xen-devel
Xen i386 xen-head.S fix sections mixup
xen-head.S does not come back to the data section, leaving the text section
as current section. It causes problems with a slightly enhanced DEBUG_RODATA
that supports CONFIG_HOTPLUG and bringing a CPU up after the text has been
marked read-only: reference to early_gdt_descr causes a page fault.
It applies on 2.6.22-rc2-mm2.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: jeremy@xensource.com
CC: chrisw@sous-sol.org
CC: virtualization@lists.osdl.org
CC: xen-devel@lists.xensource.com
---
arch/i386/xen/xen-head.S | 2 ++
1 file changed, 2 insertions(+)
Index: linux-2.6-lttng/arch/i386/xen/xen-head.S
===================================================================
--- linux-2.6-lttng.orig/arch/i386/xen/xen-head.S 2007-08-19 22:45:58.000000000 -0400
+++ linux-2.6-lttng/arch/i386/xen/xen-head.S 2007-08-19 22:46:19.000000000 -0400
@@ -13,6 +13,7 @@ ENTRY(startup_xen)
cld
movl $(init_thread_union+THREAD_SIZE),%esp
jmp xen_start_kernel
+ .previous
.pushsection ".bss.page_aligned"
.align PAGE_SIZE_asm
@@ -34,5 +35,6 @@ ENTRY(hypercall_page)
ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "no")
#endif
ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
+ .previous
#endif /*CONFIG_XEN */
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Xen i386 xen-head.S fix sections mixup
2007-08-20 3:04 [PATCH] Xen i386 xen-head.S fix sections mixup Mathieu Desnoyers
@ 2007-08-20 6:13 ` Jeremy Fitzhardinge
2007-08-20 17:19 ` [PATCH] Xen i386 xen-head.S fix sections mixup (updated) Mathieu Desnoyers
0 siblings, 1 reply; 5+ messages in thread
From: Jeremy Fitzhardinge @ 2007-08-20 6:13 UTC (permalink / raw)
To: Mathieu Desnoyers
Cc: chrisw, virtualization, Andrew Morton, xen-devel, jeremy
Mathieu Desnoyers wrote:
> Xen i386 xen-head.S fix sections mixup
>
> xen-head.S does not come back to the data section, leaving the text section
> as current section. It causes problems with a slightly enhanced DEBUG_RODATA
> that supports CONFIG_HOTPLUG and bringing a CPU up after the text has been
> marked read-only: reference to early_gdt_descr causes a page fault.
>
Thanks. It should be using pushsection/popsection.
J
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] Xen i386 xen-head.S fix sections mixup (updated)
2007-08-20 6:13 ` Jeremy Fitzhardinge
@ 2007-08-20 17:19 ` Mathieu Desnoyers
2007-08-20 17:34 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 5+ messages in thread
From: Mathieu Desnoyers @ 2007-08-20 17:19 UTC (permalink / raw)
To: Jeremy Fitzhardinge
Cc: chrisw, virtualization, Andrew Morton, xen-devel, jeremy
Xen i386 xen-head.S fix sections mixup
xen-head.S does not come back to the data section, leaving the text section
as current section. It causes problems with a slightly enhanced DEBUG_RODATA
that supports CONFIG_HOTPLUG and bringing a CPU up after the text has been
marked read-only: reference to early_gdt_descr causes a page fault.
Update:
It should be using pushsection/popsection.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: jeremy@xensource.com
CC: chrisw@sous-sol.org
CC: virtualization@lists.osdl.org
CC: xen-devel@lists.xensource.com
---
arch/i386/xen/xen-head.S | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
Index: linux-2.6-lttng/arch/i386/xen/xen-head.S
===================================================================
--- linux-2.6-lttng.orig/arch/i386/xen/xen-head.S 2007-08-20 00:22:16.000000000 -0400
+++ linux-2.6-lttng/arch/i386/xen/xen-head.S 2007-08-20 13:02:38.000000000 -0400
@@ -7,20 +7,21 @@
#include <asm/boot.h>
#include <xen/interface/elfnote.h>
- .section .init.text
+.pushsection .init.text
ENTRY(startup_xen)
movl %esi,xen_start_info
cld
movl $(init_thread_union+THREAD_SIZE),%esp
jmp xen_start_kernel
+.popsection
-.pushsection ".bss.page_aligned"
+.pushsection .bss.page_aligned
.align PAGE_SIZE_asm
ENTRY(hypercall_page)
.skip 0x1000
.popsection
- .section .text
+.pushsection .text
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")
@@ -34,5 +35,6 @@ ENTRY(hypercall_page)
ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "no")
#endif
ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
+.popsection
#endif /*CONFIG_XEN */
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Xen i386 xen-head.S fix sections mixup (updated)
2007-08-20 17:19 ` [PATCH] Xen i386 xen-head.S fix sections mixup (updated) Mathieu Desnoyers
@ 2007-08-20 17:34 ` Jeremy Fitzhardinge
2007-08-20 19:04 ` [PATCH] Xen i386 xen-head.S fix sections mixup (update 2) Mathieu Desnoyers
0 siblings, 1 reply; 5+ messages in thread
From: Jeremy Fitzhardinge @ 2007-08-20 17:34 UTC (permalink / raw)
To: Mathieu Desnoyers
Cc: chrisw, virtualization, Andrew Morton, xen-devel, jeremy
Mathieu Desnoyers wrote:
> Xen i386 xen-head.S fix sections mixup
>
> xen-head.S does not come back to the data section, leaving the text section
> as current section. It causes problems with a slightly enhanced DEBUG_RODATA
> that supports CONFIG_HOTPLUG and bringing a CPU up after the text has been
> marked read-only: reference to early_gdt_descr causes a page fault.
>
> Update:
>
> It should be using pushsection/popsection.
>
Looks good, with one caveat below.
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
> - .section .text
> +.pushsection .text
> ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
> ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
> ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")
> @@ -34,5 +35,6 @@ ENTRY(hypercall_page)
> ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "no")
> #endif
> ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
> +.popsection
>
Actually, the push/popsections around the ELFNOTEs are redundant;
ELFNOTE() does its own push/popsection to put things into the
appropriate .note* section anyway.
J
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] Xen i386 xen-head.S fix sections mixup (update 2)
2007-08-20 17:34 ` Jeremy Fitzhardinge
@ 2007-08-20 19:04 ` Mathieu Desnoyers
0 siblings, 0 replies; 5+ messages in thread
From: Mathieu Desnoyers @ 2007-08-20 19:04 UTC (permalink / raw)
To: Jeremy Fitzhardinge
Cc: chrisw, virtualization, Andrew Morton, xen-devel, jeremy
Xen i386 xen-head.S fix sections mixup
xen-head.S does not come back to the data section, leaving the text section
as current section. It causes problems with a slightly enhanced DEBUG_RODATA
that supports CONFIG_HOTPLUG and bringing a CPU up after the text has been
marked read-only: reference to early_gdt_descr causes a page fault.
Updates:
- It should be using pushsection/popsection.
- Actually, the push/popsections around the ELFNOTEs are redundant; ELFNOTE()
does its own push/popsection to put things into the appropriate .note* section
anyway.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
CC: chrisw@sous-sol.org
CC: virtualization@lists.osdl.org
CC: xen-devel@lists.xensource.com
---
arch/i386/xen/xen-head.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Index: linux-2.6-lttng/arch/i386/xen/xen-head.S
===================================================================
--- linux-2.6-lttng.orig/arch/i386/xen/xen-head.S 2007-08-20 00:22:16.000000000 -0400
+++ linux-2.6-lttng/arch/i386/xen/xen-head.S 2007-08-20 15:00:55.000000000 -0400
@@ -7,20 +7,20 @@
#include <asm/boot.h>
#include <xen/interface/elfnote.h>
- .section .init.text
+.pushsection .init.text
ENTRY(startup_xen)
movl %esi,xen_start_info
cld
movl $(init_thread_union+THREAD_SIZE),%esp
jmp xen_start_kernel
+.popsection
-.pushsection ".bss.page_aligned"
+.pushsection .bss.page_aligned
.align PAGE_SIZE_asm
ENTRY(hypercall_page)
.skip 0x1000
.popsection
- .section .text
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
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2007-08-20 3:04 [PATCH] Xen i386 xen-head.S fix sections mixup Mathieu Desnoyers
2007-08-20 6:13 ` Jeremy Fitzhardinge
2007-08-20 17:19 ` [PATCH] Xen i386 xen-head.S fix sections mixup (updated) Mathieu Desnoyers
2007-08-20 17:34 ` Jeremy Fitzhardinge
2007-08-20 19:04 ` [PATCH] Xen i386 xen-head.S fix sections mixup (update 2) Mathieu Desnoyers
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