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[31.30.174.132]) by smtp.gmail.com with ESMTPSA id f22sm1317229ejr.35.2021.04.20.23.40.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Apr 2021 23:40:57 -0700 (PDT) Date: Wed, 21 Apr 2021 08:40:55 +0200 From: Andrew Jones To: kvm@vger.kernel.org Cc: alexandru.elisei@arm.com, nikos.nikoleris@arm.com, andre.przywara@arm.com, eric.auger@redhat.com Subject: Re: [PATCH kvm-unit-tests v2 6/8] arm/arm64: setup: Consolidate memory layout assumptions Message-ID: <20210421064055.mdz3w4kgywyw5wiu@gator.home> References: <20210420190002.383444-1-drjones@redhat.com> <20210420190002.383444-7-drjones@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210420190002.383444-7-drjones@redhat.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Apr 20, 2021 at 09:00:00PM +0200, Andrew Jones wrote: > Keep as much memory layout assumptions as possible in init::start > and a single setup function. This prepares us for calling setup() > from different start functions which have been linked with different > linker scripts. To do this, stacktop is only referenced from > init::start, making freemem_start a parameter to setup(). We also > split mem_init() into three parts, one that populates the mem regions > per the DT, one that populates the mem regions per assumptions, > and one that does the mem init. The concept of a primary region > is dropped, but we add a sanity check for the absence of memory > holes, because we don't know how to deal with them yet. > > Reviewed-by: Nikos Nikoleris > Signed-off-by: Andrew Jones > --- > arm/cstart.S | 4 +- > arm/cstart64.S | 2 + > arm/flat.lds | 23 ++++++ > lib/arm/asm/setup.h | 8 +- > lib/arm/mmu.c | 2 - > lib/arm/setup.c | 173 ++++++++++++++++++++++++-------------------- > 6 files changed, 127 insertions(+), 85 deletions(-) > > diff --git a/arm/cstart.S b/arm/cstart.S > index bf3c78157e6a..446966de350d 100644 > --- a/arm/cstart.S > +++ b/arm/cstart.S > @@ -80,7 +80,9 @@ start: > > /* complete setup */ > pop {r0-r1} > - bl setup > + mov r3, #0 > + ldr r2, =stacktop @ r2,r3 is the base of free memory > + bl setup @ r0 is the addr of the dtb > > /* run the test */ > ldr r0, =__argc > diff --git a/arm/cstart64.S b/arm/cstart64.S > index 27251fe8b5cd..42ba3a3ca249 100644 > --- a/arm/cstart64.S > +++ b/arm/cstart64.S > @@ -92,6 +92,8 @@ start: > bl exceptions_init > > /* complete setup */ > + adrp x1, stacktop > + add x1, x1, :lo12:stacktop // x1 is the base of free memory > bl setup // x0 is the addr of the dtb > > /* run the test */ > diff --git a/arm/flat.lds b/arm/flat.lds > index 6ed377c0eaa0..6fb459efb815 100644 > --- a/arm/flat.lds > +++ b/arm/flat.lds > @@ -1,3 +1,26 @@ > +/* > + * init::start will pass stacktop to setup() as the base of free memory. > + * setup() will then move the FDT and initrd to that base before calling > + * mem_init(). With those movements and this linker script, we'll end up > + * having the following memory layout: > + * > + * +----------------------+ <-- top of physical memory > + * | | > + * ~ ~ > + * | | > + * +----------------------+ <-- top of initrd > + * | | > + * +----------------------+ <-- top of FDT > + * | | > + * +----------------------+ <-- top of cpu0's stack > + * | | > + * +----------------------+ <-- top of text/data/bss sections > + * | | > + * | | > + * +----------------------+ <-- load address > + * | | > + * +----------------------+ <-- physical address 0x0 > + */ > > SECTIONS > { > diff --git a/lib/arm/asm/setup.h b/lib/arm/asm/setup.h > index 210c14f818fb..f0e70b119fb0 100644 > --- a/lib/arm/asm/setup.h > +++ b/lib/arm/asm/setup.h > @@ -13,9 +13,8 @@ > extern u64 cpus[NR_CPUS]; /* per-cpu IDs (MPIDRs) */ > extern int nr_cpus; > > -#define MR_F_PRIMARY (1U << 0) > -#define MR_F_IO (1U << 1) > -#define MR_F_CODE (1U << 2) > +#define MR_F_IO (1U << 0) > +#define MR_F_CODE (1U << 1) > #define MR_F_UNKNOWN (1U << 31) > > struct mem_region { > @@ -26,6 +25,7 @@ struct mem_region { > extern struct mem_region *mem_regions; > extern phys_addr_t __phys_offset, __phys_end; > > +extern struct mem_region *mem_region_find(phys_addr_t paddr); > extern unsigned int mem_region_get_flags(phys_addr_t paddr); > > #define PHYS_OFFSET (__phys_offset) > @@ -35,6 +35,6 @@ extern unsigned int mem_region_get_flags(phys_addr_t paddr); > #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) > #define SMP_CACHE_BYTES L1_CACHE_BYTES > > -void setup(const void *fdt); > +void setup(const void *fdt, phys_addr_t freemem_start); > > #endif /* _ASMARM_SETUP_H_ */ > diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c > index 4e3cf37e33d0..10df98e7a955 100644 > --- a/lib/arm/mmu.c > +++ b/lib/arm/mmu.c > @@ -175,12 +175,10 @@ void *setup_mmu(phys_addr_t phys_end) > if (r->flags & MR_F_IO) { > continue; > } else if (r->flags & MR_F_CODE) { > - assert_msg(r->flags & MR_F_PRIMARY, "Unexpected code region"); > /* armv8 requires code shared between EL1 and EL0 to be read-only */ > mmu_set_range_ptes(mmu_idmap, r->start, r->start, r->end, > __pgprot(PTE_WBWA | PTE_USER | PTE_RDONLY)); > } else { > - assert_msg(r->flags & MR_F_PRIMARY, "Unexpected data region"); > mmu_set_range_ptes(mmu_idmap, r->start, r->start, r->end, > __pgprot(PTE_WBWA | PTE_USER)); > } > diff --git a/lib/arm/setup.c b/lib/arm/setup.c > index 7db308b70744..a5ebec3c5a12 100644 > --- a/lib/arm/setup.c > +++ b/lib/arm/setup.c > @@ -28,9 +28,10 @@ > > #include "io.h" > > -#define NR_INITIAL_MEM_REGIONS 16 > +#define MAX_DT_MEM_REGIONS 16 > +#define NR_EXTRA_MEM_REGIONS 16 > +#define NR_INITIAL_MEM_REGIONS (MAX_DT_MEM_REGIONS + NR_EXTRA_MEM_REGIONS) > > -extern unsigned long stacktop; > extern unsigned long etext; > > struct timer_state __timer_state; > @@ -75,28 +76,68 @@ static void cpu_init(void) > set_cpu_online(0, true); > } > > -unsigned int mem_region_get_flags(phys_addr_t paddr) > +static void mem_region_add(struct mem_region *r) > +{ > + struct mem_region *r_next = mem_regions; > + int i = 0; > + > + for (; r_next->end; ++r_next, ++i) > + ; > + assert(i != NR_INITIAL_MEM_REGIONS); > + > + *r_next = *r; > +} > + > +static void mem_regions_get_dt_regions(void) > +{ > + struct dt_pbus_reg regs[MAX_DT_MEM_REGIONS]; > + int nr_regs, i; > + > + nr_regs = dt_get_memory_params(regs, MAX_DT_MEM_REGIONS); > + assert(nr_regs > 0); > + > + for (i = 0; i < nr_regs; ++i) { > + mem_region_add(&(struct mem_region){ > + .start = regs[i].addr, > + .end = regs[i].addr + regs[i].size, > + }); > + } > +} > + > +struct mem_region *mem_region_find(phys_addr_t paddr) > { > struct mem_region *r; > > - for (r = mem_regions; r->end; ++r) { > + for (r = mem_regions; r->end; ++r) > if (paddr >= r->start && paddr < r->end) > - return r->flags; > - } > + return r; > + return NULL; > +} > > - return MR_F_UNKNOWN; > +unsigned int mem_region_get_flags(phys_addr_t paddr) > +{ > + struct mem_region *r = mem_region_find(paddr); > + return r ? r->flags : MR_F_UNKNOWN; > } > > -static void mem_init(phys_addr_t freemem_start) > +static void mem_regions_add_assumed(void) > { > phys_addr_t code_end = (phys_addr_t)(unsigned long)&etext; > - struct dt_pbus_reg regs[NR_INITIAL_MEM_REGIONS]; > - struct mem_region mem = { > - .start = (phys_addr_t)-1, > + struct mem_region *r; > + > + r = mem_region_find(code_end - 1); > + assert(r); > + > + /* Split the region with the code into two regions; code and data */ > + mem_region_add(&(struct mem_region){ > + .start = code_end, > + .end = r->end, > + }); > + *r = (struct mem_region){ > + .start = r->start, > + .end = code_end, > + .flags = MR_F_CODE, > }; > - struct mem_region *primary = NULL; > - phys_addr_t base, top; > - int nr_regs, nr_io = 0, i; > > /* > * mach-virt I/O regions: > @@ -104,57 +145,47 @@ static void mem_init(phys_addr_t freemem_start) > * - 512M at 256G (arm64, arm uses highmem=off) > * - 512G at 512G (arm64, arm uses highmem=off) > */ > - mem_regions[nr_io++] = (struct mem_region){ 0, (1ul << 30), MR_F_IO }; > + mem_region_add(&(struct mem_region){ 0, (1ul << 30), MR_F_IO }); > #ifdef __aarch64__ > - mem_regions[nr_io++] = (struct mem_region){ (1ul << 38), (1ul << 38) | (1ul << 29), MR_F_IO }; > - mem_regions[nr_io++] = (struct mem_region){ (1ul << 39), (1ul << 40), MR_F_IO }; > + mem_region_add(&(struct mem_region){ (1ul << 38), (1ul << 38) | (1ul << 29), MR_F_IO }); > + mem_region_add(&(struct mem_region){ (1ul << 39), (1ul << 40), MR_F_IO }); > #endif > +} > > - nr_regs = dt_get_memory_params(regs, NR_INITIAL_MEM_REGIONS - nr_io); > - assert(nr_regs > 0); > - > - for (i = 0; i < nr_regs; ++i) { > - struct mem_region *r = &mem_regions[nr_io + i]; > +static void mem_init(phys_addr_t freemem_start) > +{ > + phys_addr_t base, top; > + struct mem_region *freemem, *r, mem = { > + .start = (phys_addr_t)-1, > + }; > > - r->start = regs[i].addr; > - r->end = regs[i].addr + regs[i].size; > + freemem = mem_region_find(freemem_start); > + assert(freemem && !(freemem->flags & (MR_F_IO | MR_F_CODE))); > > - /* > - * pick the region we're in for our primary region > - */ > - if (freemem_start >= r->start && freemem_start < r->end) { > - r->flags |= MR_F_PRIMARY; > - primary = r; > + for (r = mem_regions; r->end; ++r) { > + if (!(r->flags & MR_F_IO)) { > + if (r->start < mem.start) > + mem.start = r->start; > + if (r->end > mem.end) > + mem.end = r->end; > } > - > - /* > - * set the lowest and highest addresses found, > - * ignoring potential gaps > - */ > - if (r->start < mem.start) > - mem.start = r->start; > - if (r->end > mem.end) > - mem.end = r->end; > } > - assert(primary); > + assert(mem.end); > assert(!(mem.start & ~PHYS_MASK) && !((mem.end - 1) & ~PHYS_MASK)); Eh, I promised Alex not to do this, but then didn't correct it quite right. This should be assert(!(mem.start & ~PHYS_MASK)); if ((mem.end - 1) & ~PHYS_MASK) mem.end &= PHYS_MASK; > > - __phys_offset = primary->start; /* PHYS_OFFSET */ > - __phys_end = primary->end; /* PHYS_END */ > + /* Check for holes */ > + r = mem_region_find(mem.start); > + while (r && r->end != mem.end) > + r = mem_region_find(r->end); > + assert(r); > > - /* Split the primary region into two regions; code and data */ > - mem_regions[nr_io + i] = (struct mem_region){ > - .start = code_end, > - .end = primary->end, > - .flags = MR_F_PRIMARY, > - }; > - *primary = (struct mem_region){ > - .start = primary->start, > - .end = code_end, > - .flags = MR_F_PRIMARY | MR_F_CODE, > - }; > + /* Ensure our selected freemem region is somewhere in our full range */ > + assert(freemem_start >= mem.start && freemem->end <= mem.end); > > - phys_alloc_init(freemem_start, __phys_end - freemem_start); > + __phys_offset = mem.start; /* PHYS_OFFSET */ > + __phys_end = mem.end; /* PHYS_END */ > + > + phys_alloc_init(freemem_start, freemem->end - freemem_start); > phys_alloc_set_minimum_alignment(SMP_CACHE_BYTES); > > phys_alloc_get_unused(&base, &top); > @@ -204,35 +235,17 @@ static void timer_save_state(void) > __timer_state.vtimer.irq_flags = fdt32_to_cpu(data[8]); > } > > -void setup(const void *fdt) > +void setup(const void *fdt, phys_addr_t freemem_start) > { > - void *freemem = &stacktop; > + void *freemem; > const char *bootargs, *tmp; > u32 fdt_size; > int ret; > > - /* > - * Before calling mem_init we need to move the fdt and initrd > - * to safe locations. We move them to construct the memory > - * map illustrated below: > - * > - * +----------------------+ <-- top of physical memory > - * | | > - * ~ ~ > - * | | > - * +----------------------+ <-- top of initrd > - * | | > - * +----------------------+ <-- top of FDT > - * | | > - * +----------------------+ <-- top of cpu0's stack > - * | | > - * +----------------------+ <-- top of text/data/bss sections, > - * | | see arm/flat.lds > - * | | > - * +----------------------+ <-- load address > - * | | > - * +----------------------+ > - */ > + assert(sizeof(long) == 8 || freemem_start < (3ul << 30)); > + freemem = (void *)(unsigned long)freemem_start; > + > + /* Move the FDT to the base of free memory */ > fdt_size = fdt_totalsize(fdt); > ret = fdt_move(fdt, freemem, fdt_size); > assert(ret == 0); > @@ -240,6 +253,7 @@ void setup(const void *fdt) > assert(ret == 0); > freemem += fdt_size; > > + /* Move the initrd to the top of the FDT */ > ret = dt_get_initrd(&tmp, &initrd_size); > assert(ret == 0 || ret == -FDT_ERR_NOTFOUND); > if (ret == 0) { > @@ -248,7 +262,10 @@ void setup(const void *fdt) > freemem += initrd_size; > } > > + mem_regions_get_dt_regions(); Since I have to respin for at least the mem.end assert, I think I'll rename this to mem_regions_add_dt_regions at the same time. > + mem_regions_add_assumed(); > mem_init(PAGE_ALIGN((unsigned long)freemem)); > + > cpu_init(); > > /* cpu_init must be called before thread_info_init */ > -- > 2.30.2 > Thanks, drew