From b9cede74182f8a623bc50b76d62059c0f99b7ed0 Mon Sep 17 00:00:00 2001 From: "kaf24@firebug.cl.cam.ac.uk" Date: Sun, 21 May 2006 18:55:14 +0100 Subject: [PATCH] [LOADER] Another change to the elf_paddr_offset/virt_base logic. This avoids using zero to indicate 'undefined'. Instead we use an explicit boolean to indicate whether suitable defaults should be used. As well as making the logic clearer (I believe) it also avoids problems if anyone ever explicitly specifies virt_base (and also elf_paddr_offset) as zero. Signed-off-by: Keir Fraser --- tools/libxc/xc_load_elf.c | 40 +++++++++++++++++++-------------------- xen/common/elf.c | 40 +++++++++++++++++++-------------------- 2 files changed, 38 insertions(+), 42 deletions(-) diff --git a/tools/libxc/xc_load_elf.c b/tools/libxc/xc_load_elf.c index 80256d18f8..1cb821b8b9 100644 --- a/tools/libxc/xc_load_elf.c +++ b/tools/libxc/xc_load_elf.c @@ -58,10 +58,10 @@ static int parseelfimage(const char *image, Elf_Ehdr *ehdr = (Elf_Ehdr *)image; Elf_Phdr *phdr; Elf_Shdr *shdr; - unsigned long kernstart = ~0UL, kernend=0UL, vaddr, virt_base; + unsigned long kernstart = ~0UL, kernend=0UL, vaddr, virt_base, elf_pa_off; const char *shstrtab; char *guestinfo=NULL, *p; - int h; + int h, virt_base_defined, elf_pa_off_defined; if ( !IS_ELF(*ehdr) ) { @@ -148,37 +148,35 @@ static int parseelfimage(const char *image, dsi->xen_guest_string = guestinfo; - virt_base = 0; - if ( (p = strstr(guestinfo, "VIRT_BASE=")) != NULL ) - virt_base = strtoul(p+10, &p, 0); - dsi->elf_paddr_offset = virt_base; - if ( (p = strstr(guestinfo, "ELF_PADDR_OFFSET=")) != NULL ) - dsi->elf_paddr_offset = strtoul(p+17, &p, 0); + /* Initial guess for virt_base is 0 if it is not explicitly defined. */ + p = strstr(guestinfo, "VIRT_BASE="); + virt_base_defined = (p != NULL); + virt_base = virt_base_defined ? strtoul(p+10, &p, 0) : 0; + + /* Initial guess for elf_pa_off is virt_base if not explicitly defined. */ + p = strstr(guestinfo, "ELF_PADDR_OFFSET="); + elf_pa_off_defined = (p != NULL); + elf_pa_off = elf_pa_off_defined ? strtoul(p+17, &p, 0) : virt_base; for ( h = 0; h < ehdr->e_phnum; h++ ) { phdr = (Elf_Phdr *)(image + ehdr->e_phoff + (h*ehdr->e_phentsize)); if ( !is_loadable_phdr(phdr) ) continue; - vaddr = phdr->p_paddr - dsi->elf_paddr_offset + virt_base; + vaddr = phdr->p_paddr - elf_pa_off + virt_base; if ( vaddr < kernstart ) kernstart = vaddr; if ( (vaddr + phdr->p_memsz) > kernend ) kernend = vaddr + phdr->p_memsz; } - dsi->v_start = virt_base; - if ( dsi->v_start == 0 ) - { - /* - * Legacy compatibility and images with no __xen_guest section: - * assume header addresses are virtual addresses, and that - * guest memory should be mapped starting at kernel load address. - */ - dsi->v_start = kernstart; - if ( dsi->elf_paddr_offset == 0 ) - dsi->elf_paddr_offset = dsi->v_start; - } + /* + * Legacy compatibility and images with no __xen_guest section: assume + * header addresses are virtual addresses, and that guest memory should be + * mapped starting at kernel load address. + */ + dsi->v_start = virt_base_defined ? virt_base : kernstart; + dsi->elf_paddr_offset = elf_pa_off_defined ? elf_pa_off : dsi->v_start; dsi->v_kernentry = ehdr->e_entry; if ( (p = strstr(guestinfo, "VIRT_ENTRY=")) != NULL ) diff --git a/xen/common/elf.c b/xen/common/elf.c index ef74673ab3..6fad5c5437 100644 --- a/xen/common/elf.c +++ b/xen/common/elf.c @@ -23,10 +23,10 @@ int parseelfimage(struct domain_setup_info *dsi) Elf_Ehdr *ehdr = (Elf_Ehdr *)dsi->image_addr; Elf_Phdr *phdr; Elf_Shdr *shdr; - unsigned long kernstart = ~0UL, kernend=0UL, vaddr, virt_base; + unsigned long kernstart = ~0UL, kernend=0UL, vaddr, virt_base, elf_pa_off; char *shstrtab, *guestinfo=NULL, *p; char *elfbase = (char *)dsi->image_addr; - int h; + int h, virt_base_defined, elf_pa_off_defined; if ( !elf_sanity_check(ehdr) ) return -EINVAL; @@ -84,37 +84,35 @@ int parseelfimage(struct domain_setup_info *dsi) if ( guestinfo == NULL ) guestinfo = ""; - virt_base = 0; - if ( (p = strstr(guestinfo, "VIRT_BASE=")) != NULL ) - virt_base = simple_strtoul(p+10, &p, 0); - dsi->elf_paddr_offset = virt_base; - if ( (p = strstr(guestinfo, "ELF_PADDR_OFFSET=")) != NULL ) - dsi->elf_paddr_offset = simple_strtoul(p+17, &p, 0); + /* Initial guess for virt_base is 0 if it is not explicitly defined. */ + p = strstr(guestinfo, "VIRT_BASE="); + virt_base_defined = (p != NULL); + virt_base = virt_base_defined ? simple_strtoul(p+10, &p, 0) : 0; + + /* Initial guess for elf_pa_off is virt_base if not explicitly defined. */ + p = strstr(guestinfo, "ELF_PADDR_OFFSET="); + elf_pa_off_defined = (p != NULL); + elf_pa_off = elf_pa_off_defined ? simple_strtoul(p+17, &p, 0) : virt_base; for ( h = 0; h < ehdr->e_phnum; h++ ) { phdr = (Elf_Phdr *)(elfbase + ehdr->e_phoff + (h*ehdr->e_phentsize)); if ( !is_loadable_phdr(phdr) ) continue; - vaddr = phdr->p_paddr - dsi->elf_paddr_offset + virt_base; + vaddr = phdr->p_paddr - elf_pa_off + virt_base; if ( vaddr < kernstart ) kernstart = vaddr; if ( (vaddr + phdr->p_memsz) > kernend ) kernend = vaddr + phdr->p_memsz; } - dsi->v_start = virt_base; - if ( dsi->v_start == 0 ) - { - /* - * Legacy compatibility and images with no __xen_guest section: - * assume header addresses are virtual addresses, and that - * guest memory should be mapped starting at kernel load address. - */ - dsi->v_start = kernstart; - if ( dsi->elf_paddr_offset == 0 ) - dsi->elf_paddr_offset = dsi->v_start; - } + /* + * Legacy compatibility and images with no __xen_guest section: assume + * header addresses are virtual addresses, and that guest memory should be + * mapped starting at kernel load address. + */ + dsi->v_start = virt_base_defined ? virt_base : kernstart; + dsi->elf_paddr_offset = elf_pa_off_defined ? elf_pa_off : dsi->v_start; dsi->v_kernentry = ehdr->e_entry; if ( (p = strstr(guestinfo, "VIRT_ENTRY=")) != NULL ) -- 2.30.2