Commit 2a353506 authored by Andreas Schwab's avatar Andreas Schwab Committed by Geert Uytterhoeven
Browse files

m68k: Fix assembler constraint to prevent overeager gcc optimisation 



Passing the address of a variable as an operand to an asm statement
doesn't mark the value of this variable as used, so gcc may optimize its
initialisation away.  Fix this by using the "m" constraint instead.

Signed-off-by: default avatarAndreas Schwab <schwab@linux-m68k.org>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
parent c808d3d8

arch/m68k/atari/config.c

+4 −4
Original line number Diff line number Diff line
@@ -414,9 +414,9 @@ void __init config_atari(void) 
					 * FDC val = 4 -> Supervisor only */

		asm volatile ("\n"

			"	.chip	68030\n"

			"	pmove	%0@,%/tt1\n"

			"	pmove	%0,%/tt1\n"

			"	.chip	68k"

			: : "a" (&tt1_val));

			: : "m" (tt1_val));

	} else {

	        asm volatile ("\n"

			"	.chip	68040\n"
@@ -569,10 +569,10 @@ static void atari_reset(void) 
			: "d0");

	} else

		asm volatile ("\n"

			"	pmove	%0@,%%tc\n"

			"	pmove	%0,%%tc\n"

			"	jmp	%1@"

			: /* no outputs */

			: "a" (&tc_val), "a" (reset_addr));

			: "m" (tc_val), "a" (reset_addr));

}

arch/m68k/kernel/process_mm.c

+2 −2
Original line number Diff line number Diff line
@@ -189,8 +189,8 @@ void flush_thread(void) 
	current->thread.fs = __USER_DS;

	if (!FPU_IS_EMU)

		asm volatile (".chip 68k/68881\n\t"

			      "frestore %0@\n\t"

			      ".chip 68k" : : "a" (&zero));

			      "frestore %0\n\t"

			      ".chip 68k" : : "m" (zero));

}



/*

arch/m68k/kernel/process_no.c

+2 −2
Original line number Diff line number Diff line
@@ -163,8 +163,8 @@ void flush_thread(void) 
#ifdef CONFIG_FPU

	if (!FPU_IS_EMU)

		asm volatile (".chip 68k/68881\n\t"

			      "frestore %0@\n\t"

			      ".chip 68k" : : "a" (&zero));

			      "frestore %0\n\t"

			      ".chip 68k" : : "m" (zero));

#endif

}

arch/m68k/kernel/traps.c

+17 −19
Original line number Diff line number Diff line
@@ -552,13 +552,13 @@ static inline void bus_error030 (struct frame *fp) 


#ifdef DEBUG

		asm volatile ("ptestr %3,%2@,#7,%0\n\t"

			      "pmove %%psr,%1@"

			      : "=a&" (desc)

			      : "a" (&temp), "a" (addr), "d" (ssw));

			      "pmove %%psr,%1"

			      : "=a&" (desc), "=m" (temp)

			      : "a" (addr), "d" (ssw));

#else

		asm volatile ("ptestr %2,%1@,#7\n\t"

			      "pmove %%psr,%0@"

			      : : "a" (&temp), "a" (addr), "d" (ssw));

			      "pmove %%psr,%0"

			      : "=m" (temp) : "a" (addr), "d" (ssw));

#endif

		mmusr = temp;
@@ -605,20 +605,18 @@ static inline void bus_error030 (struct frame *fp) 
			       !(ssw & RW) ? "write" : "read", addr,

			       fp->ptregs.pc, ssw);

			asm volatile ("ptestr #1,%1@,#0\n\t"

				      "pmove %%psr,%0@"

				      : /* no outputs */

				      : "a" (&temp), "a" (addr));

				      "pmove %%psr,%0"

				      : "=m" (temp)

				      : "a" (addr));

			mmusr = temp;



			printk ("level 0 mmusr is %#x\n", mmusr);

#if 0

			asm volatile ("pmove %%tt0,%0@"

				      : /* no outputs */

				      : "a" (&tlong));

			asm volatile ("pmove %%tt0,%0"

				      : "=m" (tlong));

			printk("tt0 is %#lx, ", tlong);

			asm volatile ("pmove %%tt1,%0@"

				      : /* no outputs */

				      : "a" (&tlong));

			asm volatile ("pmove %%tt1,%0"

				      : "=m" (tlong));

			printk("tt1 is %#lx\n", tlong);

#endif

#ifdef DEBUG
@@ -668,13 +666,13 @@ static inline void bus_error030 (struct frame *fp) 


#ifdef DEBUG

	asm volatile ("ptestr #1,%2@,#7,%0\n\t"

		      "pmove %%psr,%1@"

		      : "=a&" (desc)

		      : "a" (&temp), "a" (addr));

		      "pmove %%psr,%1"

		      : "=a&" (desc), "=m" (temp)

		      : "a" (addr));

#else

	asm volatile ("ptestr #1,%1@,#7\n\t"

		      "pmove %%psr,%0@"

		      : : "a" (&temp), "a" (addr));

		      "pmove %%psr,%0"

		      : "=m" (temp) : "a" (addr));

#endif

	mmusr = temp;

arch/m68k/mm/cache.c

+3 −3
Original line number Diff line number Diff line
@@ -52,9 +52,9 @@ static unsigned long virt_to_phys_slow(unsigned long vaddr) 
		unsigned long *descaddr;



		asm volatile ("ptestr %3,%2@,#7,%0\n\t"

			      "pmove %%psr,%1@"

			      : "=a&" (descaddr)

			      : "a" (&mmusr), "a" (vaddr), "d" (get_fs().seg));

			      "pmove %%psr,%1"

			      : "=a&" (descaddr), "=m" (mmusr)

			      : "a" (vaddr), "d" (get_fs().seg));

		if (mmusr & (MMU_I|MMU_B|MMU_L))

			return 0;

		descaddr = phys_to_virt((unsigned long)descaddr);

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