parisc: enable wide mode early (6b1370ae) · Commits · 戴 / test

The idle task might have been allocated above 4GB. With the current code we cannot access that memory because the CPU is still running in narrow mode. This was found on a J5000 machine and the patch is required to enable SPARSEMEM on that machine. Signed-off-by:

Sven Schnelle <svens@stackframe.org> Signed-off-by:

Helge Deller <deller@gmx.de>

arch/parisc/kernel/head.S

+13 −0

Original line number	Original line	Diff line number	Diff line
	@@ -329,6 +329,19 @@ smp_slave_stext:
	mtsp %r0,%sr6		mtsp %r0,%sr6
	mtsp %r0,%sr7		mtsp %r0,%sr7

			#ifdef CONFIG_64BIT
			/*
			* Enable Wide mode early, in case the task_struct for the idle
			* task in smp_init_current_idle_task was allocated above 4GB.
			*/
			1: mfia %rp /* clear upper part of pcoq */
			ldo 2f-1b(%rp),%rp
			depdi 0,31,32,%rp
			bv (%rp)
			ssm PSW_SM_W,%r0
			2:
			#endif

	/* Initialize the SP - monarch sets up smp_init_current_idle_task */		/* Initialize the SP - monarch sets up smp_init_current_idle_task */
	load32 PA(smp_init_current_idle_task),%sp		load32 PA(smp_init_current_idle_task),%sp
	LDREG 0(%sp),%sp /* load task address */		LDREG 0(%sp),%sp /* load task address */

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