parisc: Use lpa instruction to load physical addresses in driver code (116d7533) · Commits · 戴 / test

Most I/O in the kernel is done using the kernel offset mapping. However, there is one API that uses aliased kernel address ranges: > The final category of APIs is for I/O to deliberately aliased address > ranges inside the kernel. Such aliases are set up by use of the > vmap/vmalloc API. Since kernel I/O goes via physical pages, the I/O > subsystem assumes that the user mapping and kernel offset mapping are > the only aliases. This isn't true for vmap aliases, so anything in > the kernel trying to do I/O to vmap areas must manually manage > coherency. It must do this by flushing the vmap range before doing > I/O and invalidating it after the I/O returns. For this reason, we should use the hardware lpa instruction to load the physical address of kernel virtual addresses in the driver code. I believe we only use the vmap/vmalloc API with old PA 1.x processors which don't have a sba, so we don't hit this problem. Tested on c3750, c8000 and rp3440. Signed-off-by:

John David Anglin <dave.anglin@bell.net> Signed-off-by:

Helge Deller <deller@gmx.de>

arch/parisc/include/asm/special_insns.h

+24 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,30 @@
		#ifndef __PARISC_SPECIAL_INSNS_H
		#define __PARISC_SPECIAL_INSNS_H

		#define lpa(va) ({ \
		unsigned long pa; \
		__asm__ __volatile__( \
		"copy %%r0,%0\n\t" \
		"lpa %%r0(%1),%0" \
		: "=r" (pa) \
		: "r" (va) \
		: "memory" \
		); \
		pa; \
		})

		#define lpa_user(va) ({ \
		unsigned long pa; \
		__asm__ __volatile__( \
		"copy %%r0,%0\n\t" \
		"lpa %%r0(%%sr3,%1),%0" \
		: "=r" (pa) \
		: "r" (va) \
		: "memory" \
		); \
		pa; \
		})

		#define mfctl(reg) ({ \
		unsigned long cr; \
		__asm__ __volatile__( \

drivers/parisc/ccio-dma.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -570,7 +570,7 @@ ccio_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
		** "hints" parm includes the VALID bit!
		** "dep" clobbers the physical address offset bits as well.
		*/
		pa = virt_to_phys(vba);
		pa = lpa(vba);
		asm volatile("depw %1,31,12,%0" : "+r" (pa) : "r" (hints));
		((u32 *)pdir_ptr)[1] = (u32) pa;

drivers/parisc/sba_iommu.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -572,7 +572,7 @@ sba_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
		u64 pa; /* physical address */
		register unsigned ci; /* coherent index */

		pa = virt_to_phys(vba);
		pa = lpa(vba);
		pa &= IOVP_MASK;

		asm("lci 0(%1), %0" : "=r" (ci) : "r" (vba));

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