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Commit c5a37394 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x32: Signal-related system calls 



x32 uses the 64-bit signal frame format, obviously, but there are some
structures which mixes that with pointers or sizeof(long) types, as
such we have to create a handful of system calls specific to x32.  By
and large these are a mixture of the 64-bit and the compat system
calls.

Originally-by: default avatarH. J. Lu <hjl.tools@gmail.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent a96d692e

arch/x86/kernel/entry_64.S

+19 −0
Original line number Diff line number Diff line
@@ -746,6 +746,25 @@ ENTRY(stub_rt_sigreturn) 
	CFI_ENDPROC

END(stub_rt_sigreturn)



#ifdef CONFIG_X86_X32_ABI

	PTREGSCALL stub_x32_sigaltstack, sys32_sigaltstack, %rdx



ENTRY(stub_x32_rt_sigreturn)

	CFI_STARTPROC

	addq $8, %rsp

	PARTIAL_FRAME 0

	SAVE_REST

	movq %rsp,%rdi

	FIXUP_TOP_OF_STACK %r11

	call sys32_x32_rt_sigreturn

	movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer

	RESTORE_REST

	jmp int_ret_from_sys_call

	CFI_ENDPROC

END(stub_x32_rt_sigreturn)



#endif



/*

 * Build the entry stubs and pointer table with some assembler magic.

 * We pack 7 stubs into a single 32-byte chunk, which will fit in a

arch/x86/kernel/signal.c

+117 −1
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#ifdef CONFIG_X86_64

#include <asm/proto.h>

#include <asm/ia32_unistd.h>

#include <asm/sys_ia32.h>

#endif /* CONFIG_X86_64 */



#include <asm/syscall.h>
@@ -632,6 +633,16 @@ static int signr_convert(int sig) 
#define is_ia32	0

#endif /* CONFIG_IA32_EMULATION */



#ifdef CONFIG_X86_X32_ABI

#define is_x32	test_thread_flag(TIF_X32)



static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,

			      siginfo_t *info, compat_sigset_t *set,

			      struct pt_regs *regs);

#else /* !CONFIG_X86_X32_ABI */

#define is_x32	0

#endif /* CONFIG_X86_X32_ABI */



int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

		sigset_t *set, struct pt_regs *regs);

int ia32_setup_frame(int sig, struct k_sigaction *ka,
@@ -656,8 +667,14 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 
			ret = ia32_setup_rt_frame(usig, ka, info, set, regs);

		else

			ret = ia32_setup_frame(usig, ka, set, regs);

	} else

#ifdef CONFIG_X86_X32_ABI

	} else if (is_x32) {

		ret = x32_setup_rt_frame(usig, ka, info,

					 (compat_sigset_t *)set, regs);

#endif

	} else {

		ret = __setup_rt_frame(sig, ka, info, set, regs);

	}



	if (ret) {

		force_sigsegv(sig, current);
@@ -840,3 +857,102 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where) 


	force_sig(SIGSEGV, me);

}



#ifdef CONFIG_X86_X32_ABI

static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,

			      siginfo_t *info, compat_sigset_t *set,

			      struct pt_regs *regs)

{

	struct rt_sigframe_x32 __user *frame;

	void __user *restorer;

	int err = 0;

	void __user *fpstate = NULL;



	frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);



	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

		return -EFAULT;



	if (ka->sa.sa_flags & SA_SIGINFO) {

		if (copy_siginfo_to_user32(&frame->info, info))

			return -EFAULT;

	}



	put_user_try {

		/* Create the ucontext.  */

		if (cpu_has_xsave)

			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);

		else

			put_user_ex(0, &frame->uc.uc_flags);

		put_user_ex(0, &frame->uc.uc_link);

		put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);

		put_user_ex(sas_ss_flags(regs->sp),

			    &frame->uc.uc_stack.ss_flags);

		put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);

		put_user_ex(0, &frame->uc.uc__pad0);

		err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,

					regs, set->sig[0]);

		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));



		if (ka->sa.sa_flags & SA_RESTORER) {

			restorer = ka->sa.sa_restorer;

		} else {

			/* could use a vstub here */

			restorer = NULL;

			err |= -EFAULT;

		}

		put_user_ex(restorer, &frame->pretcode);

	} put_user_catch(err);



	if (err)

		return -EFAULT;



	/* Set up registers for signal handler */

	regs->sp = (unsigned long) frame;

	regs->ip = (unsigned long) ka->sa.sa_handler;



	/* We use the x32 calling convention here... */

	regs->di = sig;

	regs->si = (unsigned long) &frame->info;

	regs->dx = (unsigned long) &frame->uc;



	loadsegment(ds, __USER_DS);

	loadsegment(es, __USER_DS);



	regs->cs = __USER_CS;

	regs->ss = __USER_DS;



	return 0;

}



asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)

{

	struct rt_sigframe_x32 __user *frame;

	sigset_t set;

	unsigned long ax;

	struct pt_regs tregs;



	frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);



	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))

		goto badframe;

	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))

		goto badframe;



	sigdelsetmask(&set, ~_BLOCKABLE);

	set_current_blocked(&set);



	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))

		goto badframe;



	tregs = *regs;

	if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)

		goto badframe;



	return ax;



badframe:

	signal_fault(regs, frame, "x32 rt_sigreturn");

	return 0;

}

#endif