Re: [kvm-unit-tests PATCH v2 13/18] arm64: Simplify efi_mem_init

[Andrew Jones <andrew.jones@linux.dev>]

On Mon, Mar 04, 2024 at 08:10:40AM +0000, Nikos Nikoleris wrote:
> On 27/02/2024 19:21, Andrew Jones wrote:
> > Reduce the EFI mem_map loop to only setting flags and finding the
> > largest free memory region. Then, apply memregions_split() for
> > the code/data region split and do the rest of the things that
> > used to be done in the EFI mem_map loop in a separate mem_region
> > loop.
> > 
> > Signed-off-by: Andrew Jones <andrew.jones@linux.dev>
> 
> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

Thanks. While skimming this patch now to remind myself about it for v3,
I see the etext = ALIGN() below which I forgot to consider. We certainly
need the end of the text section to be on a page boundary, but that
doesn't seem to be the case right now. I think we need to add this
change

diff --git a/arm/efi/elf_aarch64_efi.lds b/arm/efi/elf_aarch64_efi.lds
index 836d98255d88..7a4192b77900 100644
--- a/arm/efi/elf_aarch64_efi.lds
+++ b/arm/efi/elf_aarch64_efi.lds
@@ -13,6 +13,7 @@ SECTIONS
     *(.rodata*)
     . = ALIGN(16);
   }
+  . = ALIGN(4096);
   _etext = .;
   _text_size = . - _text;
   .dynamic  : { *(.dynamic) }

Thanks,
drew

> 
> Thanks,
> 
> Nikos
> 
> > ---
> >   lib/arm/setup.c | 45 ++++++++++++++++++++-------------------------
> >   1 file changed, 20 insertions(+), 25 deletions(-)
> > 
> > diff --git a/lib/arm/setup.c b/lib/arm/setup.c
> > index d0be4c437708..631597b343f1 100644
> > --- a/lib/arm/setup.c
> > +++ b/lib/arm/setup.c
> > @@ -301,9 +301,7 @@ static efi_status_t efi_mem_init(efi_bootinfo_t *efi_bootinfo)
> >   	struct efi_boot_memmap *map = &(efi_bootinfo->mem_map);
> >   	efi_memory_desc_t *buffer = *map->map;
> >   	efi_memory_desc_t *d = NULL;
> > -	struct mem_region r;
> > -	uintptr_t text = (uintptr_t)&_text, etext = ALIGN((uintptr_t)&_etext, 4096);
> > -	uintptr_t data = (uintptr_t)&_data, edata = ALIGN((uintptr_t)&_edata, 4096);
> > +	struct mem_region r, *code, *data;
> >   	const void *fdt = efi_bootinfo->fdt;
> >   	/*
> > @@ -337,21 +335,7 @@ static efi_status_t efi_mem_init(efi_bootinfo_t *efi_bootinfo)
> >   			r.flags = MR_F_IO;
> >   			break;
> >   		case EFI_LOADER_CODE:
> > -			if (r.start <= text && r.end > text) {
> > -				/* This is the unit test region. Flag the code separately. */
> > -				phys_addr_t tmp = r.end;
> > -
> > -				assert(etext <= data);
> > -				assert(edata <= r.end);
> > -				r.flags = MR_F_CODE;
> > -				r.end = data;
> > -				memregions_add(&r);
> > -				r.start = data;
> > -				r.end = tmp;
> > -				r.flags = 0;
> > -			} else {
> > -				r.flags = MR_F_RESERVED;
> > -			}
> > +			r.flags = MR_F_CODE;
> >   			break;
> >   		case EFI_CONVENTIONAL_MEMORY:
> >   			if (free_mem_pages < d->num_pages) {
> > @@ -361,15 +345,27 @@ static efi_status_t efi_mem_init(efi_bootinfo_t *efi_bootinfo)
> >   			break;
> >   		}
> > -		if (!(r.flags & MR_F_IO)) {
> > -			if (r.start < __phys_offset)
> > -				__phys_offset = r.start;
> > -			if (r.end > __phys_end)
> > -				__phys_end = r.end;
> > -		}
> >   		memregions_add(&r);
> >   	}
> > +	memregions_split((unsigned long)&_etext, &code, &data);
> > +	assert(code && (code->flags & MR_F_CODE));
> > +	if (data)
> > +		data->flags &= ~MR_F_CODE;
> > +
> > +	for (struct mem_region *m = mem_regions; m->end; ++m) {
> > +		if (m != code && (m->flags & MR_F_CODE))
> > +			m->flags = MR_F_RESERVED;
> > +
> > +		if (!(m->flags & MR_F_IO)) {
> > +			if (m->start < __phys_offset)
> > +				__phys_offset = m->start;
> > +			if (m->end > __phys_end)
> > +				__phys_end = m->end;
> > +		}
> > +	}
> > +	__phys_end &= PHYS_MASK;
> > +
> >   	if (efi_bootinfo->fdt_valid) {
> >   		unsigned long old_start = free_mem_start;
> >   		void *freemem = (void *)free_mem_start;
> > @@ -380,7 +376,6 @@ static efi_status_t efi_mem_init(efi_bootinfo_t *efi_bootinfo)
> >   		free_mem_pages = (free_mem_start - old_start) >> EFI_PAGE_SHIFT;
> >   	}
> > -	__phys_end &= PHYS_MASK;
> >   	asm_mmu_disable();
> >   	if (free_mem_pages == 0)