lmb: change the return code on lmb_alloc_addr()

Ben reports a failure to boot the kernel on hardware that starts its
physical memory from 0x0.
The reason is that lmb_alloc_addr(), which is supposed to reserve a
specific address, takes the address as the first argument, but then also
returns the address for success or failure and treats 0 as a failure.

Since we already know the address change the prototype to return an int.

Reported-by: Ben Schneider <ben@bens.haus>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
---
 fs/fs.c                     |  2 +-
 include/lmb.h               |  6 ++---
 lib/efi_loader/efi_memory.c |  3 +--
 lib/lmb.c                   |  6 ++---
 test/lib/lmb.c              | 53 +++++++++++++++++++------------------
 5 files changed, 35 insertions(+), 35 deletions(-)

On Friday, March 14th, 2025 at 3:57 AM, Ilias Apalodimas <ilias.apalodimas@linaro.org> wrote:

> 
> 
> Ben reports a failure to boot the kernel on hardware that starts its
> physical memory from 0x0.
> The reason is that lmb_alloc_addr(), which is supposed to reserve a
> specific address, takes the address as the first argument, but then also
> returns the address for success or failure and treats 0 as a failure.
> 
> Since we already know the address change the prototype to return an int.
> 
> Reported-by: Ben Schneider ben@bens.haus
> 
> Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org
> 
> ---
> fs/fs.c | 2 +-
> include/lmb.h | 6 ++---
> lib/efi_loader/efi_memory.c | 3 +--
> lib/lmb.c | 6 ++---
> test/lib/lmb.c | 53 +++++++++++++++++++------------------
> 5 files changed, 35 insertions(+), 35 deletions(-)
> 
> diff --git a/fs/fs.c b/fs/fs.c
> index 99ddcc5e37be..1ed7c0f2d2c7 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -554,7 +554,7 @@ static int fs_read_lmb_check(const char filename, ulong addr, loff_t offset,
> 
> lmb_dump_all();
> 
> - if (lmb_alloc_addr(addr, read_len, LMB_NONE) == addr)
> + if (!lmb_alloc_addr(addr, read_len, LMB_NONE))
> return 0;
> 
> log_err("* Reading file would overwrite reserved memory \n");
> diff --git a/include/lmb.h b/include/lmb.h
> index 09297a4f530a..0d316c64c0a3 100644
> --- a/include/lmb.h
> +++ b/include/lmb.h
> @@ -135,9 +135,9 @@ phys_addr_t lmb_alloc_base(phys_size_t size, ulong align, phys_addr_t max_addr,
> * parameter. The base parameter is used to specify the base address
> * of the requested region.
> *
> - * Return: Base address on success, 0 on error.
> + * Return: 0 on success -1 on error
> /
> -phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size, u32 flags);
> +int lmb_alloc_addr(phys_addr_t base, phys_size_t size, u32 flags);
> 
> /
> * lmb_is_reserved_flags() - Test if address is in reserved region with flag
> @@ -175,7 +175,7 @@ void lmb_pop(struct lmb store);
> 
> static inline int lmb_read_check(phys_addr_t addr, phys_size_t len)
> {
> - return lmb_alloc_addr(addr, len, LMB_NONE) == addr ? 0 : -1;
> + return lmb_alloc_addr(addr, len, LMB_NONE);
> }
> 
> /
> diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
> index 6d00b1862505..c39b53922bb4 100644
> --- a/lib/efi_loader/efi_memory.c
> +++ b/lib/efi_loader/efi_memory.c
> @@ -491,8 +491,7 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type type,
> return EFI_NOT_FOUND;
> 
> addr = map_to_sysmem((void *)(uintptr_t)*memory);
> - addr = (u64)lmb_alloc_addr(addr, len, flags);
> - if (!addr)
> + if (lmb_alloc_addr(addr, len, flags))
> return EFI_NOT_FOUND;
> break;
> default:
> diff --git a/lib/lmb.c b/lib/lmb.c
> index 93fc1bea07cd..61bb13dc4e24 100644
> --- a/lib/lmb.c
> +++ b/lib/lmb.c
> @@ -714,7 +714,7 @@ phys_addr_t lmb_alloc_base(phys_size_t size, ulong align, phys_addr_t max_addr,
> return alloc;
> }
> 
> -phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size, u32 flags)
> +int lmb_alloc_addr(phys_addr_t base, phys_size_t size, u32 flags)
> {
> long rgn;
> struct lmb_region lmb_memory = lmb.available_mem.data;
> @@ -731,11 +731,11 @@ phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size, u32 flags)
> base + size - 1, 1)) {
> / ok, reserve the memory /
> if (!lmb_reserve(base, size, flags))
> - return base;
> + return 0;
> }
> }
> 
> - return 0;
> + return -1;
> }
> 
> / Return number of bytes from a given address that are free */
> diff --git a/test/lib/lmb.c b/test/lib/lmb.c
> index fcb5f1af532a..01b1c7fdedd0 100644
> --- a/test/lib/lmb.c
> +++ b/test/lib/lmb.c
> @@ -531,21 +531,21 @@ static int test_alloc_addr(struct unit_test_state uts, const phys_addr_t ram)
> 
> / Try to allocate a page twice */
> b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
> - ut_asserteq(b, alloc_addr_a);
> - b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NOOVERWRITE);
> ut_asserteq(b, 0);
> + b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NOOVERWRITE);
> + ut_asserteq(b, -1);
> b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
> - ut_asserteq(b, alloc_addr_a);
> + ut_asserteq(b, 0);
> b = lmb_alloc_addr(alloc_addr_a, 0x2000, LMB_NONE);
> - ut_asserteq(b, alloc_addr_a);
> + ut_asserteq(b, 0);
> ret = lmb_free(alloc_addr_a, 0x2000);
> ut_asserteq(ret, 0);
> b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NOOVERWRITE);
> - ut_asserteq(b, alloc_addr_a);
> - b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
> ut_asserteq(b, 0);
> + b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
> + ut_asserteq(b, -1);
> b = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NOOVERWRITE);
> - ut_asserteq(b, 0);
> + ut_asserteq(b, -1);
> ret = lmb_free(alloc_addr_a, 0x1000);
> ut_asserteq(ret, 0);
> 
> @@ -561,22 +561,22 @@ static int test_alloc_addr(struct unit_test_state uts, const phys_addr_t ram)
> 
> / allocate blocks */
> a = lmb_alloc_addr(ram, alloc_addr_a - ram, LMB_NONE);
> - ut_asserteq(a, ram);
> + ut_asserteq(a, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 3, ram, 0x8010000,
> alloc_addr_b, 0x10000, alloc_addr_c, 0x10000);
> b = lmb_alloc_addr(alloc_addr_a + 0x10000,
> alloc_addr_b - alloc_addr_a - 0x10000, LMB_NONE);
> - ut_asserteq(b, alloc_addr_a + 0x10000);
> + ut_asserteq(b, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, ram, 0x10010000,
> alloc_addr_c, 0x10000, 0, 0);
> c = lmb_alloc_addr(alloc_addr_b + 0x10000,
> alloc_addr_c - alloc_addr_b - 0x10000, LMB_NONE);
> - ut_asserteq(c, alloc_addr_b + 0x10000);
> + ut_asserteq(c, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, 0x18010000,
> 0, 0, 0, 0);
> d = lmb_alloc_addr(alloc_addr_c + 0x10000,
> ram_end - alloc_addr_c - 0x10000, LMB_NONE);
> - ut_asserteq(d, alloc_addr_c + 0x10000);
> + ut_asserteq(d, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, ram_size,
> 0, 0, 0, 0);
> 
> @@ -586,57 +586,58 @@ static int test_alloc_addr(struct unit_test_state uts, const phys_addr_t ram)
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, ram_size,
> 0, 0, 0, 0);
> 
> - ret = lmb_free(d, ram_end - alloc_addr_c - 0x10000);
> + / free thge allocation from d /
> + ret = lmb_free(alloc_addr_c + 0x10000, ram_end - alloc_addr_c - 0x10000);
> ut_asserteq(ret, 0);
> 
> / allocate at 3 points in free range /
> 
> d = lmb_alloc_addr(ram_end - 4, 4, LMB_NONE);
> - ut_asserteq(d, ram_end - 4);
> + ut_asserteq(d, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, ram, 0x18010000,
> - d, 4, 0, 0);
> - ret = lmb_free(d, 4);
> + ram_end - 4, 4, 0, 0);
> + ret = lmb_free(ram_end - 4, 4);
> ut_asserteq(ret, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, 0x18010000,
> 0, 0, 0, 0);
> 
> d = lmb_alloc_addr(ram_end - 128, 4, LMB_NONE);
> - ut_asserteq(d, ram_end - 128);
> + ut_asserteq(d, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, ram, 0x18010000,
> - d, 4, 0, 0);
> - ret = lmb_free(d, 4);
> + ram_end - 128, 4, 0, 0);
> + ret = lmb_free(ram_end - 128, 4);
> ut_asserteq(ret, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, 0x18010000,
> 0, 0, 0, 0);
> 
> d = lmb_alloc_addr(alloc_addr_c + 0x10000, 4, LMB_NONE);
> - ut_asserteq(d, alloc_addr_c + 0x10000);
> + ut_asserteq(d, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, 0x18010004,
> 0, 0, 0, 0);
> - ret = lmb_free(d, 4);
> + ret = lmb_free(alloc_addr_c + 0x10000, 4);
> ut_asserteq(ret, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram, 0x18010000,
> 0, 0, 0, 0);
> 
> - / allocate at the bottom /
> - ret = lmb_free(a, alloc_addr_a - ram);
> + / allocate at the bottom a was assigned to ram at the top /
> + ret = lmb_free(ram, alloc_addr_a - ram);
> ut_asserteq(ret, 0);
> ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, ram + 0x8000000,
> 0x10010000, 0, 0, 0, 0);
> 
> d = lmb_alloc_addr(ram, 4, LMB_NONE);
> - ut_asserteq(d, ram);
> - ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, d, 4,
> + ut_asserteq(d, 0);
> + ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, ram, 4,
> ram + 0x8000000, 0x10010000, 0, 0);
> 
> / check that allocating outside memory fails */
> if (ram_end != 0) {
> ret = lmb_alloc_addr(ram_end, 1, LMB_NONE);
> - ut_asserteq(ret, 0);
> + ut_asserteq(ret, -1);
> }
> if (ram != 0) {
> ret = lmb_alloc_addr(ram - 1, 1, LMB_NONE);
> - ut_asserteq(ret, 0);
> + ut_asserteq(ret, -1);
> }
> 
> lmb_pop(&store);
> --
> 2.47.2

Tested-by: Ben Schneider <ben@bens.haus>

[...]

> > ret = lmb_alloc_addr(ram - 1, 1, LMB_NONE);
> > - ut_asserteq(ret, 0);
> > + ut_asserteq(ret, -1);
> > }
> >
> > lmb_pop(&store);
> > --
> > 2.47.2
>
> Tested-by: Ben Schneider <ben@bens.haus>

Thanks Ben.
Especially for the testing and the whole debugging saga

/Ilias