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Commit 41e2e8fd authored by Russell King's avatar Russell King
Browse files

ARM: Tighten check for allowable CPSR values 



Reviewed-by: default avatarArve Hjønnevåg <arve@android.com>
Acked-by: default avatarDima Zavin <dima@android.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 21d93e2e

arch/arm/include/asm/ptrace.h

+13 −4
Original line number Diff line number Diff line
@@ -158,15 +158,24 @@ struct pt_regs { 
 */

static inline int valid_user_regs(struct pt_regs *regs)

{

	if (user_mode(regs) && (regs->ARM_cpsr & PSR_I_BIT) == 0) {

	unsigned long mode = regs->ARM_cpsr & MODE_MASK;



	/*

	 * Always clear the F (FIQ) and A (delayed abort) bits

	 */

	regs->ARM_cpsr &= ~(PSR_F_BIT | PSR_A_BIT);



	if ((regs->ARM_cpsr & PSR_I_BIT) == 0) {

		if (mode == USR_MODE)

			return 1;

		if (elf_hwcap & HWCAP_26BIT && mode == USR26_MODE)

			return 1;

	}



	/*

	 * Force CPSR to something logical...

	 */

	regs->ARM_cpsr &= PSR_f | PSR_s | (PSR_x & ~PSR_A_BIT) | PSR_T_BIT | MODE32_BIT;

	regs->ARM_cpsr &= PSR_f | PSR_s | PSR_x | PSR_T_BIT | MODE32_BIT;

	if (!(elf_hwcap & HWCAP_26BIT))

		regs->ARM_cpsr |= USR_MODE;