Hi Drew, On 4/20/21 7:59 PM, Andrew Jones wrote: > By providing a proper ioremap function, we can just rely on devices > calling it for each region they need (as they already do) instead of > mapping a big assumed I/O range. We don't require the MMU to be > enabled at the time of the ioremap. In that case, we add the mapping > to the identity map anyway. This allows us to call setup_vm after > io_init. Why don't we just call setup_vm before io_init, I hear you > ask? Well, that's because tests like sieve want to start with the MMU > off, later call setup_vm, and all the while have working I/O. Some > unit tests are just really demanding... > > Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx> > --- > lib/arm/asm/io.h | 6 ++++++ > lib/arm/asm/mmu.h | 1 + > lib/arm/asm/page.h | 2 ++ > lib/arm/mmu.c | 37 +++++++++++++++++++++++++++---------- > lib/arm64/asm/io.h | 6 ++++++ > lib/arm64/asm/mmu.h | 1 + > lib/arm64/asm/page.h | 2 ++ > 7 files changed, 45 insertions(+), 10 deletions(-) > > diff --git a/lib/arm/asm/io.h b/lib/arm/asm/io.h > index ba3b0b2412ad..e4caa6ff5d1e 100644 > --- a/lib/arm/asm/io.h > +++ b/lib/arm/asm/io.h > @@ -77,6 +77,12 @@ static inline void __raw_writel(u32 val, volatile void __iomem *addr) > : "r" (val)); > } > > +#define ioremap ioremap > +static inline void __iomem *ioremap(phys_addr_t phys_addr, size_t size) > +{ > + return __ioremap(phys_addr, size); > +} > + > #define virt_to_phys virt_to_phys > static inline phys_addr_t virt_to_phys(const volatile void *x) > { > diff --git a/lib/arm/asm/mmu.h b/lib/arm/asm/mmu.h > index 122874b8aebe..d88a4f16df42 100644 > --- a/lib/arm/asm/mmu.h > +++ b/lib/arm/asm/mmu.h > @@ -12,6 +12,7 @@ > #define PTE_SHARED L_PTE_SHARED > #define PTE_AF PTE_EXT_AF > #define PTE_WBWA L_PTE_MT_WRITEALLOC > +#define PTE_UNCACHED L_PTE_MT_UNCACHED > > /* See B3.18.7 TLB maintenance operations */ > > diff --git a/lib/arm/asm/page.h b/lib/arm/asm/page.h > index 1fb5cd26ac66..8eb4a883808e 100644 > --- a/lib/arm/asm/page.h > +++ b/lib/arm/asm/page.h > @@ -47,5 +47,7 @@ typedef struct { pteval_t pgprot; } pgprot_t; > extern phys_addr_t __virt_to_phys(unsigned long addr); > extern unsigned long __phys_to_virt(phys_addr_t addr); > > +extern void *__ioremap(phys_addr_t phys_addr, size_t size); > + > #endif /* !__ASSEMBLY__ */ > #endif /* _ASMARM_PAGE_H_ */ > diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c > index 15eef007f256..ee0c79142ba1 100644 > --- a/lib/arm/mmu.c > +++ b/lib/arm/mmu.c > @@ -11,6 +11,7 @@ > #include <asm/mmu.h> > #include <asm/setup.h> > #include <asm/page.h> > +#include <asm/io.h> > > #include "alloc_page.h" > #include "vmalloc.h" > @@ -157,9 +158,8 @@ void mmu_set_range_sect(pgd_t *pgtable, uintptr_t virt_offset, > void *setup_mmu(phys_addr_t phys_end) > { > uintptr_t code_end = (uintptr_t)&etext; > - struct mem_region *r; > > - /* 0G-1G = I/O, 1G-3G = identity, 3G-4G = vmalloc */ > + /* 3G-4G region is reserved for vmalloc, cap phys_end at 3G */ > if (phys_end > (3ul << 30)) > phys_end = 3ul << 30; > > @@ -170,14 +170,8 @@ void *setup_mmu(phys_addr_t phys_end) > "Unsupported translation granule %ld\n", PAGE_SIZE); > #endif > > - mmu_idmap = alloc_page(); > - > - for (r = mem_regions; r->end; ++r) { > - if (!(r->flags & MR_F_IO)) > - continue; > - mmu_set_range_sect(mmu_idmap, r->start, r->start, r->end, > - __pgprot(PMD_SECT_UNCACHED | PMD_SECT_USER)); > - } > + if (!mmu_idmap) > + mmu_idmap = alloc_page(); > > /* armv8 requires code shared between EL1 and EL0 to be read-only */ > mmu_set_range_ptes(mmu_idmap, PHYS_OFFSET, > @@ -192,6 +186,29 @@ void *setup_mmu(phys_addr_t phys_end) > return mmu_idmap; > } > > +void __iomem *__ioremap(phys_addr_t phys_addr, size_t size) > +{ > + phys_addr_t paddr_aligned = phys_addr & PAGE_MASK; > + phys_addr_t paddr_end = PAGE_ALIGN(phys_addr + size); > + pgprot_t prot = __pgprot(PTE_UNCACHED | PTE_USER); >From ARM DDI 0487G.a, page B-171: "Hardware does not prevent speculative instruction fetches from a memory location with any of the Device memory attributes unless the memory location is also marked as execute-never for all Exception levels. *Note* This means that to prevent speculative instruction fetches from memory locations with Device memory attributes, any location that is assigned any Device memory type must also be marked as execute-never for all Exception levels. Failure to mark a memory location with any Device memory attribute as execute-never for all Exception levels is a programming error." I think that should also be PTE_UXN | PTE_PXN (the kernel defines it the same way). Otherwise looks good. Thanks, Alex > + pgd_t *pgtable; > + > + assert(sizeof(long) == 8 || !(phys_addr >> 32)); > + > + if (mmu_enabled()) { > + pgtable = current_thread_info()->pgtable; > + } else { > + if (!mmu_idmap) > + mmu_idmap = alloc_page(); > + pgtable = mmu_idmap; > + } > + > + mmu_set_range_ptes(pgtable, paddr_aligned, paddr_aligned, > + paddr_end, prot); > + > + return (void __iomem *)(unsigned long)phys_addr; > +} > + > phys_addr_t __virt_to_phys(unsigned long addr) > { > if (mmu_enabled()) { > diff --git a/lib/arm64/asm/io.h b/lib/arm64/asm/io.h > index e0a03b250d5b..be19f471c0fa 100644 > --- a/lib/arm64/asm/io.h > +++ b/lib/arm64/asm/io.h > @@ -71,6 +71,12 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) > return val; > } > > +#define ioremap ioremap > +static inline void __iomem *ioremap(phys_addr_t phys_addr, size_t size) > +{ > + return __ioremap(phys_addr, size); > +} > + > #define virt_to_phys virt_to_phys > static inline phys_addr_t virt_to_phys(const volatile void *x) > { > diff --git a/lib/arm64/asm/mmu.h b/lib/arm64/asm/mmu.h > index 72d75eafc882..72371b2d9fe3 100644 > --- a/lib/arm64/asm/mmu.h > +++ b/lib/arm64/asm/mmu.h > @@ -8,6 +8,7 @@ > #include <asm/barrier.h> > > #define PMD_SECT_UNCACHED PMD_ATTRINDX(MT_DEVICE_nGnRE) > +#define PTE_UNCACHED PTE_ATTRINDX(MT_DEVICE_nGnRE) > #define PTE_WBWA PTE_ATTRINDX(MT_NORMAL) > > static inline void flush_tlb_all(void) > diff --git a/lib/arm64/asm/page.h b/lib/arm64/asm/page.h > index ae4484b22114..d0fac6ea563d 100644 > --- a/lib/arm64/asm/page.h > +++ b/lib/arm64/asm/page.h > @@ -72,5 +72,7 @@ typedef struct { pteval_t pgprot; } pgprot_t; > extern phys_addr_t __virt_to_phys(unsigned long addr); > extern unsigned long __phys_to_virt(phys_addr_t addr); > > +extern void *__ioremap(phys_addr_t phys_addr, size_t size); > + > #endif /* !__ASSEMBLY__ */ > #endif /* _ASMARM64_PAGE_H_ */