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ec85bd369f
When offset is larger than the size of the bit array, we should not attempt to access the array as we can perform an access beyond the end of the array. Fix this by changing the pre-condition. Using "cmp r2, r1; bhs ..." covers us for the size == 0 case, since this will always take the branch when r1 is zero, irrespective of the value of r2. This means we can fix this bug without adding any additional code! Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
193 lines
4.7 KiB
ArmAsm
193 lines
4.7 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* linux/arch/arm/lib/findbit.S
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*
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* Copyright (C) 1995-2000 Russell King
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*
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* 16th March 2001 - John Ripley <jripley@sonicblue.com>
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* Fixed so that "size" is an exclusive not an inclusive quantity.
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* All users of these functions expect exclusive sizes, and may
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* also call with zero size.
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* Reworked by rmk.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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.text
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/*
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* Purpose : Find a 'zero' bit
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* Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
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*/
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ENTRY(_find_first_zero_bit_le)
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teq r1, #0
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beq 3f
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mov r2, #0
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1:
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ARM( ldrb r3, [r0, r2, lsr #3] )
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THUMB( lsr r3, r2, #3 )
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THUMB( ldrb r3, [r0, r3] )
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eors r3, r3, #0xff @ invert bits
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: cmp r2, r1 @ any more?
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blo 1b
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3: mov r0, r1 @ no free bits
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ret lr
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ENDPROC(_find_first_zero_bit_le)
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/*
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* Purpose : Find next 'zero' bit
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* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
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*/
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ENTRY(_find_next_zero_bit_le)
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cmp r2, r1
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bhs 3b
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ands ip, r2, #7
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beq 1b @ If new byte, goto old routine
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ARM( ldrb r3, [r0, r2, lsr #3] )
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THUMB( lsr r3, r2, #3 )
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THUMB( ldrb r3, [r0, r3] )
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eor r3, r3, #0xff @ now looking for a 1 bit
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movs r3, r3, lsr ip @ shift off unused bits
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bne .L_found
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orr r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(_find_next_zero_bit_le)
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/*
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* Purpose : Find a 'one' bit
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* Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
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*/
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ENTRY(_find_first_bit_le)
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teq r1, #0
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beq 3f
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mov r2, #0
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1:
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ARM( ldrb r3, [r0, r2, lsr #3] )
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THUMB( lsr r3, r2, #3 )
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THUMB( ldrb r3, [r0, r3] )
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movs r3, r3
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: cmp r2, r1 @ any more?
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blo 1b
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3: mov r0, r1 @ no free bits
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ret lr
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ENDPROC(_find_first_bit_le)
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/*
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* Purpose : Find next 'one' bit
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* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
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*/
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ENTRY(_find_next_bit_le)
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cmp r2, r1
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bhs 3b
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ands ip, r2, #7
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beq 1b @ If new byte, goto old routine
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ARM( ldrb r3, [r0, r2, lsr #3] )
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THUMB( lsr r3, r2, #3 )
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THUMB( ldrb r3, [r0, r3] )
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movs r3, r3, lsr ip @ shift off unused bits
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bne .L_found
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orr r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(_find_next_bit_le)
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#ifdef __ARMEB__
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ENTRY(_find_first_zero_bit_be)
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teq r1, #0
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beq 3f
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mov r2, #0
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1: eor r3, r2, #0x18 @ big endian byte ordering
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ARM( ldrb r3, [r0, r3, lsr #3] )
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THUMB( lsr r3, #3 )
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THUMB( ldrb r3, [r0, r3] )
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eors r3, r3, #0xff @ invert bits
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: cmp r2, r1 @ any more?
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blo 1b
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3: mov r0, r1 @ no free bits
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ret lr
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ENDPROC(_find_first_zero_bit_be)
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ENTRY(_find_next_zero_bit_be)
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cmp r2, r1
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bhs 3b
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ands ip, r2, #7
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beq 1b @ If new byte, goto old routine
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eor r3, r2, #0x18 @ big endian byte ordering
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ARM( ldrb r3, [r0, r3, lsr #3] )
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THUMB( lsr r3, #3 )
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THUMB( ldrb r3, [r0, r3] )
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eor r3, r3, #0xff @ now looking for a 1 bit
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movs r3, r3, lsr ip @ shift off unused bits
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bne .L_found
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orr r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(_find_next_zero_bit_be)
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ENTRY(_find_first_bit_be)
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teq r1, #0
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beq 3f
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mov r2, #0
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1: eor r3, r2, #0x18 @ big endian byte ordering
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ARM( ldrb r3, [r0, r3, lsr #3] )
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THUMB( lsr r3, #3 )
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THUMB( ldrb r3, [r0, r3] )
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movs r3, r3
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: cmp r2, r1 @ any more?
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blo 1b
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3: mov r0, r1 @ no free bits
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ret lr
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ENDPROC(_find_first_bit_be)
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ENTRY(_find_next_bit_be)
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cmp r2, r1
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bhs 3b
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ands ip, r2, #7
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beq 1b @ If new byte, goto old routine
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eor r3, r2, #0x18 @ big endian byte ordering
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ARM( ldrb r3, [r0, r3, lsr #3] )
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THUMB( lsr r3, #3 )
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THUMB( ldrb r3, [r0, r3] )
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movs r3, r3, lsr ip @ shift off unused bits
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bne .L_found
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orr r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(_find_next_bit_be)
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#endif
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/*
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* One or more bits in the LSB of r3 are assumed to be set.
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*/
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.L_found:
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#if __LINUX_ARM_ARCH__ >= 5
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rsb r0, r3, #0
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and r3, r3, r0
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clz r3, r3
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rsb r3, r3, #31
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add r0, r2, r3
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#else
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tst r3, #0x0f
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addeq r2, r2, #4
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movne r3, r3, lsl #4
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tst r3, #0x30
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addeq r2, r2, #2
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movne r3, r3, lsl #2
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tst r3, #0x40
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addeq r2, r2, #1
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mov r0, r2
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#endif
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cmp r1, r0 @ Clamp to maxbit
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movlo r0, r1
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ret lr
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