Previous commits that dealt with get_user for 64bit type missed to export proper functions, so if get_user macro with particular target/value types are used by kernel module modpost would produce 'undefined!' error. Solution is to export all required functions. Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
virt_to_page() is incredibly inefficient when virt-to-phys patching is
enabled. This is because we end up with this calculation:
page = &mem_map[asm virt_to_phys(addr) >> 12 - __pv_phys_offset >> 12]
in assembly. The asm virt_to_phys() is equivalent this this operation:
addr - PAGE_OFFSET + __pv_phys_offset
and we can see that because this is assembly, the compiler has no chance
to optimise some of that away. This should reduce down to:
page = &mem_map[(addr - PAGE_OFFSET) >> 12]
for the common cases. Permit the compiler to make this optimisation by
giving it more of the information it needs - do this by providing a
virt_to_pfn() macro.
Another issue which makes this more complex is that __pv_phys_offset is
a 64-bit type on all platforms. This is needlessly wasteful - if we
store the physical offset as a PFN, we can save a lot of work having
to deal with 64-bit values, which sometimes ends up producing incredibly
horrid code:
a4c: e3009000 movw r9, #0
a4c: R_ARM_MOVW_ABS_NC __pv_phys_offset
a50: e3409000 movt r9, #0 ; r9 = &__pv_phys_offset
a50: R_ARM_MOVT_ABS __pv_phys_offset
a54: e3002000 movw r2, #0
a54: R_ARM_MOVW_ABS_NC __pv_phys_offset
a58: e3402000 movt r2, #0 ; r2 = &__pv_phys_offset
a58: R_ARM_MOVT_ABS __pv_phys_offset
a5c: e5999004 ldr r9, [r9, #4] ; r9 = high word of __pv_phys_offset
a60: e3001000 movw r1, #0
a60: R_ARM_MOVW_ABS_NC mem_map
a64: e592c000 ldr ip, [r2] ; ip = low word of __pv_phys_offset
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Enable the compiler intrinsic for byte swapping on arch ARM. This allows the compiler to detect and be able to optimize out byte swappings, and has a very modest benefit on vmlinux size (Linaro gcc 4.8): text data bss dec hex filename 2840310 123932 61960 3026202 2e2d1a vmlinux-lart #orig 2840152 123932 61960 3026044 2e2c7c vmlinux-lart #builtin-bswap 6473120 314840 5616016 12403976 bd4508 vmlinux-mxs #orig 6472586 314848 5616016 12403450 bd42fa vmlinux-mxs #builtin-bswap 7419872 318372 379556 8117800 7bde28 vmlinux-imx_v6_v7 #orig 7419170 318364 379556 8117090 7bdb62 vmlinux-imx_v6_v7 #builtin-bswap Signed-off-by: Kim Phillips <kim.phillips@freescale.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current phys_to_virt patching mechanism works only for 32 bit
physical addresses and this patch extends the idea for 64bit physical
addresses.
The 64bit v2p patching mechanism patches the higher 8 bits of physical
address with a constant using 'mov' instruction and lower 32bits are patched
using 'add'. While this is correct, in those platforms where the lowmem addressable
physical memory spawns across 4GB boundary, a carry bit can be produced as a
result of addition of lower 32bits. This has to be taken in to account and added
in to the upper. The patched __pv_offset and va are added in lower 32bits, where
__pv_offset can be in two's complement form when PA_START < VA_START and that can
result in a false carry bit.
e.g
1) PA = 0x80000000; VA = 0xC0000000
__pv_offset = PA - VA = 0xC0000000 (2's complement)
2) PA = 0x2 80000000; VA = 0xC000000
__pv_offset = PA - VA = 0x1 C0000000
So adding __pv_offset + VA should never result in a true overflow for (1).
So in order to differentiate between a true carry, a __pv_offset is extended
to 64bit and the upper 32bits will have 0xffffffff if __pv_offset is
2's complement. So 'mvn #0' is inserted instead of 'mov' while patching
for the same reason. Since mov, add, sub instruction are to patched
with different constants inside the same stub, the rotation field
of the opcode is using to differentiate between them.
So the above examples for v2p translation becomes for VA=0xC0000000,
1) PA[63:32] = 0xffffffff
PA[31:0] = VA + 0xC0000000 --> results in a carry
PA[63:32] = PA[63:32] + carry
PA[63:0] = 0x0 80000000
2) PA[63:32] = 0x1
PA[31:0] = VA + 0xC0000000 --> results in a carry
PA[63:32] = PA[63:32] + carry
PA[63:0] = 0x2 80000000
The above ideas were suggested by Nicolas Pitre <nico@linaro.org> as
part of the review of first and second versions of the subject patch.
There is no corresponding change on the phys_to_virt() side, because
computations on the upper 32-bits would be discarded anyway.
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
This patch allows a timer-based delay implementation to be selected by switching the delay routines over to use get_cycles, which is implemented in terms of read_current_timer. This further allows us to skip the loop calibration and have a consistent delay function in the face of core frequency scaling. To avoid the pain of dealing with memory-mapped counters, this implementation uses the co-processor interface to the architected timers when they are available. The previous loop-based implementation is kept around for CPUs without the architected timers and we retain both the maximum delay (2ms) and the corresponding conversion factors for determining the number of loops required for a given interval. Since the indirection of the timer routines will only work when called from C, the sa1100 sleep routines are modified to branch to the loop-based delay functions directly. Tested-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch implements the word-at-a-time interface for ARM using the same algorithm as x86. We use the fls macro from ARMv5 onwards, where we have a clz instruction available which saves us a mov instruction when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001 constant. Big-endian configurations make use of the implementation from asm-generic. With this implemented, we can replace our byte-at-a-time strnlen_user and strncpy_from_user functions with the optimised generic versions. Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Disintegrate asm/system.h for ARM. Signed-off-by: David Howells <dhowells@redhat.com> cc: Russell King <linux@arm.linux.org.uk> cc: linux-arm-kernel@lists.infradead.org
Many of the core ARM kernel files are not modules, but just including module.h for exporting symbols. Now these files can use the lighter footprint export.h for this role. There are probably lots more, but ARM files of mach-* and plat-* don't get coverage via a simple yesconfig build. They will have to be cleaned up and tested via using their respective configs. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Currently, show_regs calls __backtrace which does nothing if CONFIG_FRAME_POINTER is not set. Switch to dump_stack which handles both CONFIG_FRAME_POINTER and CONFIG_ARM_UNWIND correctly. __backtrace is now superseded by dump_stack in general and show_regs was the last caller so remove __backtrace as well. Signed-off-by: Laura Abbott <lauraa@codeaurora.org> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>