android_kernel_motorola_sm6225/include
Jeremy Fitzhardinge f29192320f x86/pgtable: explain constant sign extension problem
When the _PAGE_FOO constants are defined as (1ul << _PAGE_BIT_FOO), they
become unsigned longs.  In 32-bit PAE mode, these end up being
implicitly cast to 64-bit types when used to manipulate a pte, and
because they're unsigned the top 32-bits are 0, destroying the upper
bits of the pte.

When _PAGE_FOO constants are given a signed integer type, the cast to
64-bits will sign-extend so that the upper bits are all ones,
preserving the upper pte bits in manipulations.

Explain this in a prominent place.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:59 +01:00
..
acpi x86: dummy placeholder for acpi/reboot.h 2008-01-30 13:31:17 +01:00
asm-alpha
asm-arm ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-avr32
asm-blackfin
asm-cris
asm-frv
asm-generic percpu: make the asm-generic/percpu.h more "generic" 2008-01-30 13:32:52 +01:00
asm-h8300
asm-ia64 percpu: move arch XX_PER_CPU_XX definitions into linux/percpu.h 2008-01-30 13:32:52 +01:00
asm-m32r core: remove last users of empty FASTCALL macro 2008-01-30 13:31:17 +01:00
asm-m68k ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-m68knommu ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-mips [MIPS] Malta, Atlas: move an extern function declaration to the header file 2008-01-29 10:15:05 +00:00
asm-parisc
asm-powerpc percpu: move arch XX_PER_CPU_XX definitions into linux/percpu.h 2008-01-30 13:32:52 +01:00
asm-ppc
asm-s390 percpu: move arch XX_PER_CPU_XX definitions into linux/percpu.h 2008-01-30 13:32:52 +01:00
asm-sh
asm-sparc
asm-sparc64 percpu: move arch XX_PER_CPU_XX definitions into linux/percpu.h 2008-01-30 13:32:52 +01:00
asm-um git-x86: unbreak UML 2008-01-30 13:32:38 +01:00
asm-v850
asm-x86 x86/pgtable: explain constant sign extension problem 2008-01-30 13:32:59 +01:00
asm-xtensa
crypto
keys
linux x86: kprobes: add kprobes smoke tests that run on boot 2008-01-30 13:32:53 +01:00
math-emu
media
mtd
net [NET_SCHED]: act_api: use PTR_ERR in tcf_action_init/tcf_action_get 2008-01-28 15:11:17 -08:00
pcmcia
rdma
rxrpc
scsi
sound
video
xen x86: page.h: make pte_t a union to always include 2008-01-30 13:32:57 +01:00
Kbuild