From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Clark Date: Wed, 26 Jul 2017 09:55:58 -0400 Subject: [U-Boot] [PATCH 2/3] efi_loader: add checking for incorrect use of EFI_ENTRY/EXIT In-Reply-To: <20170726135559.16653-1-robdclark@gmail.com> References: <20170726135559.16653-1-robdclark@gmail.com> Message-ID: <20170726135559.16653-2-robdclark@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Missing an EFI_ENTRY() or doubling up EFI_EXIT() leads to non-obvious crashes. Let's add some error checking. Signed-off-by: Rob Clark --- include/efi_loader.h | 5 +++++ lib/efi_loader/efi_boottime.c | 13 +++++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/efi_loader.h b/include/efi_loader.h index 09bab7dbc6..4b49fac84b 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -15,11 +15,13 @@ #include +int __efi_check_nesting(int delta); /* * Enter the u-boot world from UEFI: */ #define EFI_ENTRY(format, ...) do { \ efi_restore_gd(); \ + assert(__efi_check_nesting(+1)); \ debug("EFI: Entry %s(" format ")\n", __func__, ##__VA_ARGS__); \ } while(0) @@ -28,6 +30,7 @@ */ #define EFI_EXIT(ret) ({ \ debug("EFI: Exit: %s: %u\n", __func__, (u32)((ret) & ~EFI_ERROR_MASK)); \ + assert(__efi_check_nesting(-1)); \ efi_exit_func(ret); \ }) @@ -36,10 +39,12 @@ */ #define EFI_CALL(exp) do { \ debug("EFI: Call: %s\n", #exp); \ + assert(__efi_check_nesting(-1)); \ efi_exit_func(EFI_SUCCESS); \ exp; \ efi_restore_gd(); \ debug("EFI: Return From: %s\n", #exp); \ + assert(__efi_check_nesting(+1)); \ } while(0) extern struct efi_runtime_services efi_runtime_services; diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index 76cafffc1d..b21df7bd5d 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -57,6 +57,17 @@ void efi_save_gd(void) #endif } +/* Check for incorrect use of EFI_ENTRY() / EFI_EXIT() */ +int __efi_check_nesting(int delta) +{ + static int entry_count; + /* post-increment, pre-decrement: */ + if (delta > 0) + return entry_count++ == 0; + else + return --entry_count == 0; +} + /* Called on every callback entry */ void efi_restore_gd(void) { @@ -716,7 +727,9 @@ static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle, return EFI_EXIT(info->exit_status); } + __efi_check_nesting(-1); entry(image_handle, &systab); + __efi_check_nesting(+1); /* Should usually never get here */ return EFI_EXIT(EFI_SUCCESS); -- 2.13.0