c6x: remove architecture

The c6x architecture was added to the kernel in 2011 at a time when
running Linux on DSPs was widely seen as the logical evolution.
It appears the trend has gone back to running Linux on Arm based SoCs
with DSP, using a better supported software ecosystem, and having better
real-time behavior for the DSP code. An example of this is TI's own
Keystone2 platform.

The upstream kernel port appears to no longer have any users. Mark
Salter remained avaialable to review patches, but mentioned that
he no longer has access to working hardware himself. Without any
users, it's best to just remove the code completely to reduce the
work for cross-architecture code changes.

Many thanks to Mark for maintaining the code for the past ten years.

Link: https://lore.kernel.org/lkml/41dc7795afda9f776d8cd0d3075f776cf586e97c.camel@redhat.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 322 deletions

diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c
deleted file mode 100644
index 862460c3b183..000000000000
--- a/arch/c6x/kernel/signal.c
+++ /dev/null
@@ -1,322 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  Port on Texas Instruments TMS320C6x architecture
- *
- *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
- *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
- *
- *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
- */
-
-#include <linux/kernel.h>
-#include <linux/uaccess.h>
-#include <linux/syscalls.h>
-#include <linux/tracehook.h>
-
-#include <asm/asm-offsets.h>
-#include <asm/ucontext.h>
-#include <asm/cacheflush.h>
-
-
-/*
- * Do a signal return, undo the signal stack.
- */
-
-#define RETCODE_SIZE (9 << 2)	/* 9 instructions = 36 bytes */
-
-struct rt_sigframe {
-	struct siginfo __user *pinfo;
-	void __user *puc;
-	struct siginfo info;
-	struct ucontext uc;
-	unsigned long retcode[RETCODE_SIZE >> 2];
-};
-
-static int restore_sigcontext(struct pt_regs *regs,
-			      struct sigcontext __user *sc)
-{
-	int err = 0;
-
-	/* The access_ok check was done by caller, so use __get_user here */
-#define COPY(x)  (err |= __get_user(regs->x, &sc->sc_##x))
-
-	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
-	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
-	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
-
-	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
-	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
-	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
-	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
-	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
-	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
-	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
-	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
-
-	COPY(csr); COPY(pc);
-
-#undef COPY
-
-	return err;
-}
-
-asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
-{
-	struct rt_sigframe __user *frame;
-	sigset_t set;
-
-	/* Always make any pending restarted system calls return -EINTR */
-	current->restart_block.fn = do_no_restart_syscall;
-
-	/*
-	 * Since we stacked the signal on a dword boundary,
-	 * 'sp' should be dword aligned here.  If it's
-	 * not, then the user is trying to mess with us.
-	 */
-	if (regs->sp & 7)
-		goto badframe;
-
-	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
-
-	if (!access_ok(frame, sizeof(*frame)))
-		goto badframe;
-	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
-		goto badframe;
-
-	set_current_blocked(&set);
-
-	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
-		goto badframe;
-
-	return regs->a4;
-
-badframe:
-	force_sig(SIGSEGV);
-	return 0;
-}
-
-static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
-			    unsigned long mask)
-{
-	int err = 0;
-
-	err |= __put_user(mask, &sc->sc_mask);
-
-	/* The access_ok check was done by caller, so use __put_user here */
-#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
-
-	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
-	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
-	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
-
-	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
-	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
-	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
-	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
-	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
-	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
-	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
-	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
-
-	COPY(csr); COPY(pc);
-
-#undef COPY
-
-	return err;
-}
-
-static inline void __user *get_sigframe(struct ksignal *ksig,
-					struct pt_regs *regs,
-					unsigned long framesize)
-{
-	unsigned long sp = sigsp(regs->sp, ksig);
-
-	/*
-	 * No matter what happens, 'sp' must be dword
-	 * aligned. Otherwise, nasty things will happen
-	 */
-	return (void __user *)((sp - framesize) & ~7);
-}
-
-static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
-			  struct pt_regs *regs)
-{
-	struct rt_sigframe __user *frame;
-	unsigned long __user *retcode;
-	int err = 0;
-
-	frame = get_sigframe(ksig, regs, sizeof(*frame));
-
-	if (!access_ok(frame, sizeof(*frame)))
-		return -EFAULT;
-
-	err |= __put_user(&frame->info, &frame->pinfo);
-	err |= __put_user(&frame->uc, &frame->puc);
-	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
-
-	/* Clear all the bits of the ucontext we don't use.  */
-	err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
-
-	err |= setup_sigcontext(&frame->uc.uc_mcontext,	regs, set->sig[0]);
-	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
-
-	/* Set up to return from userspace */
-	retcode = (unsigned long __user *) &frame->retcode;
-
-	/* The access_ok check was done above, so use __put_user here */
-#define COPY(x) (err |= __put_user(x, retcode++))
-
-	COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
-				/* MVK __NR_rt_sigreturn,B0 */
-	COPY(0x10000000UL);	/* SWE */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-	COPY(0x00006000UL);	/* NOP 4 */
-
-#undef COPY
-
-	if (err)
-		return -EFAULT;
-
-	flush_icache_range((unsigned long) &frame->retcode,
-			   (unsigned long) &frame->retcode + RETCODE_SIZE);
-
-	retcode = (unsigned long __user *) &frame->retcode;
-
-	/* Change user context to branch to signal handler */
-	regs->sp = (unsigned long) frame - 8;
-	regs->b3 = (unsigned long) retcode;
-	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
-
-	/* Give the signal number to the handler */
-	regs->a4 = ksig->sig;
-
-	/*
-	 * For realtime signals we must also set the second and third
-	 * arguments for the signal handler.
-	 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
-	 */
-	regs->b4 = (unsigned long)&frame->info;
-	regs->a6 = (unsigned long)&frame->uc;
-
-	return 0;
-}
-
-static inline void
-handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
-{
-	switch (regs->a4) {
-	case -ERESTARTNOHAND:
-		if (!has_handler)
-			goto do_restart;
-		regs->a4 = -EINTR;
-		break;
-
-	case -ERESTARTSYS:
-		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
-			regs->a4 = -EINTR;
-			break;
-		}
-		fallthrough;
-	case -ERESTARTNOINTR:
-do_restart:
-		regs->a4 = regs->orig_a4;
-		regs->pc -= 4;
-		break;
-	}
-}
-
-/*
- * handle the actual delivery of a signal to userspace
- */
-static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
-			  int syscall)
-{
-	int ret;
-
-	/* Are we from a system call? */
-	if (syscall) {
-		/* If so, check system call restarting.. */
-		switch (regs->a4) {
-		case -ERESTART_RESTARTBLOCK:
-		case -ERESTARTNOHAND:
-			regs->a4 = -EINTR;
-			break;
-
-		case -ERESTARTSYS:
-			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
-				regs->a4 = -EINTR;
-				break;
-			}
-
-			fallthrough;
-		case -ERESTARTNOINTR:
-			regs->a4 = regs->orig_a4;
-			regs->pc -= 4;
-		}
-	}
-
-	/* Set up the stack frame */
-	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
-	signal_setup_done(ret, ksig, 0);
-}
-
-/*
- * handle a potential signal
- */
-static void do_signal(struct pt_regs *regs, int syscall)
-{
-	struct ksignal ksig;
-
-	/* we want the common case to go fast, which is why we may in certain
-	 * cases get here from kernel mode */
-	if (!user_mode(regs))
-		return;
-
-	if (get_signal(&ksig)) {
-		handle_signal(&ksig, regs, syscall);
-		return;
-	}
-
-	/* did we come from a system call? */
-	if (syscall) {
-		/* restart the system call - no handlers present */
-		switch (regs->a4) {
-		case -ERESTARTNOHAND:
-		case -ERESTARTSYS:
-		case -ERESTARTNOINTR:
-			regs->a4 = regs->orig_a4;
-			regs->pc -= 4;
-			break;
-
-		case -ERESTART_RESTARTBLOCK:
-			regs->a4 = regs->orig_a4;
-			regs->b0 = __NR_restart_syscall;
-			regs->pc -= 4;
-			break;
-		}
-	}
-
-	/* if there's no signal to deliver, we just put the saved sigmask
-	 * back */
-	restore_saved_sigmask();
-}
-
-/*
- * notification of userspace execution resumption
- * - triggered by current->work.notify_resume
- */
-asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
-				 int syscall)
-{
-	/* deal with pending signal delivery */
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
-		do_signal(regs, syscall);
-
-	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME))
-		tracehook_notify_resume(regs);
-}