Commit 643d703d authored by Suzuki K Poulose's avatar Suzuki K Poulose Committed by Will Deacon
Browse files

arm64: compat: Check for AArch32 state 



Make sure we have AArch32 state available for running COMPAT
binaries and also for switching the personality to PER_LINUX32.

Signed-off-by: default avatarYury Norov <ynorov@caviumnetworks.com>
[ Added cap bit, checks for HWCAP, personality ]
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: default avatarYury Norov <ynorov@caviumnetworks.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 042446a3

arch/arm64/include/asm/elf.h

+2 −1
Original line number Diff line number Diff line
@@ -177,7 +177,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; 


/* AArch32 EABI. */

#define EF_ARM_EABI_MASK		0xff000000

#define compat_elf_check_arch(x)	(((x)->e_machine == EM_ARM) && \

#define compat_elf_check_arch(x)	(system_supports_32bit_el0() && \

					 ((x)->e_machine == EM_ARM) && \

					 ((x)->e_flags & EF_ARM_EABI_MASK))



#define compat_start_thread		compat_start_thread

arch/arm64/kernel/cpufeature.c

+5 −2
Original line number Diff line number Diff line
@@ -987,6 +987,7 @@ void verify_local_cpu_capabilities(void) 


	verify_local_cpu_features(arm64_features);

	verify_local_elf_hwcaps(arm64_elf_hwcaps);

	if (system_supports_32bit_el0())

		verify_local_elf_hwcaps(compat_elf_hwcaps);

}
@@ -1004,6 +1005,8 @@ void __init setup_cpu_features(void) 
	/* Set the CPU feature capabilies */

	setup_feature_capabilities();

	setup_elf_hwcaps(arm64_elf_hwcaps);



	if (system_supports_32bit_el0())

		setup_elf_hwcaps(compat_elf_hwcaps);



	/* Advertise that we have computed the system capabilities */

arch/arm64/kernel/sys.c

+10 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/syscalls.h>

#include <asm/cpufeature.h>



asmlinkage long sys_mmap(unsigned long addr, unsigned long len,

			 unsigned long prot, unsigned long flags,
@@ -36,11 +37,20 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len, 
	return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);

}



SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)

{

	if (personality(personality) == PER_LINUX32 &&

		!system_supports_32bit_el0())

		return -EINVAL;

	return sys_personality(personality);

}



/*

 * Wrappers to pass the pt_regs argument.

 */

asmlinkage long sys_rt_sigreturn_wrapper(void);

#define sys_rt_sigreturn	sys_rt_sigreturn_wrapper

#define sys_personality		sys_arm64_personality



#undef __SYSCALL

#define __SYSCALL(nr, sym)	[nr] = sym,

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