Commit Graph

3 Commits

Author SHA1 Message Date
Hugh Dickins c34d1b4d16 [PATCH] mm: kill check_user_page_readable
check_user_page_readable is a problematic variant of follow_page.  It's used
only by oprofile's i386 and arm backtrace code, at interrupt time, to
establish whether a userspace stackframe is currently readable.

This is problematic, because we want to push the page_table_lock down inside
follow_page, and later split it; whereas oprofile is doing a spin_trylock on
it (in the i386 case, forgotten in the arm case), and needs that to pin
perhaps two pages spanned by the stackframe (which might be covered by
different locks when we split).

I think oprofile is going about this in the wrong way: it doesn't need to know
the area is readable (neither i386 nor arm uses read protection of user
pages), it doesn't need to pin the memory, it should simply
__copy_from_user_inatomic, and see if that succeeds or not.  Sorry, but I've
not got around to devising the sparse __user annotations for this.

Then we can eliminate check_user_page_readable, and return to a single
follow_page without the __follow_page variants.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:41 -07:00
Richard Purdie c013622d5f [PATCH] ARM: 2838/1: Fix arm oprofile backtrace warning
Patch from Richard Purdie

Fix a typo causing a warning in the arm oprofile backtrace code.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-04 15:06:59 +01:00
Richard Purdie fa0ebff62a [PATCH] ARM: 2761/1: OProfile: Add call graphing support for arm
Patch from Richard Purdie

Add functions to generate backtraces of both kernel and user processes
which allows oprofile's call graphing functionality to be used on arm.
This requires unstripped binaries/libs which use a frame pointer.

Signed-off-by: Richard Purdie
Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-28 21:01:03 +01:00