From 53c258787427ea43ebfa76fefa6534cae507e521 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 12 May 2008 14:01:47 -0700 Subject: uml: redo host capability detection and disabling Redo how host capabilities are recorded at startup and disabled on the command line. There are now explicit variables saying what's been disabled by the command line rather than the implicitness of the have_* variable being zero. The capability variables now start at zero and are set to one as their capabilities are found to be present on the host. Signed-off-by: Jeff Dike Cc: WANG Cong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/start_up.c | 81 +++++++++++++++++++++++---------------------- 1 file changed, 41 insertions(+), 40 deletions(-) (limited to 'arch/um/os-Linux/start_up.c') diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c index 997d01944f91..b4b36e0f2e89 100644 --- a/arch/um/os-Linux/start_up.c +++ b/arch/um/os-Linux/start_up.c @@ -23,6 +23,7 @@ #include "mem_user.h" #include "ptrace_user.h" #include "registers.h" +#include "skas.h" #include "skas_ptrace.h" static void ptrace_child(void) @@ -140,14 +141,27 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit) } /* Changed only during early boot */ -int ptrace_faultinfo = 1; -int ptrace_ldt = 1; -int proc_mm = 1; -int skas_needs_stub = 0; +int ptrace_faultinfo; +static int disable_ptrace_faultinfo; + +int ptrace_ldt; +static int disable_ptrace_ldt; + +int proc_mm; +static int disable_proc_mm; + +int have_switch_mm; +static int disable_switch_mm; + +int skas_needs_stub; static int __init skas0_cmd_param(char *str, int* add) { - ptrace_faultinfo = proc_mm = 0; + disable_ptrace_faultinfo = 1; + disable_ptrace_ldt = 1; + disable_proc_mm = 1; + disable_switch_mm = 1; + return 0; } @@ -157,15 +171,12 @@ static int __init mode_skas0_cmd_param(char *str, int* add) __attribute__((alias("skas0_cmd_param"))); __uml_setup("skas0", skas0_cmd_param, - "skas0\n" - " Disables SKAS3 usage, so that SKAS0 is used, unless \n" - " you specify mode=tt.\n\n"); +"skas0\n" +" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used\n\n"); __uml_setup("mode=skas0", mode_skas0_cmd_param, - "mode=skas0\n" - " Disables SKAS3 usage, so that SKAS0 is used, unless you \n" - " specify mode=tt. Note that this was recently added - on \n" - " older kernels you must use simply \"skas0\".\n\n"); +"mode=skas0\n" +" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used.\n\n"); /* Changed only during early boot */ static int force_sysemu_disabled = 0; @@ -360,7 +371,7 @@ void __init os_early_checks(void) static int __init noprocmm_cmd_param(char *str, int* add) { - proc_mm = 0; + disable_proc_mm = 1; return 0; } @@ -372,7 +383,7 @@ __uml_setup("noprocmm", noprocmm_cmd_param, static int __init noptracefaultinfo_cmd_param(char *str, int* add) { - ptrace_faultinfo = 0; + disable_ptrace_faultinfo = 1; return 0; } @@ -384,7 +395,7 @@ __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param, static int __init noptraceldt_cmd_param(char *str, int* add) { - ptrace_ldt = 0; + disable_ptrace_ldt = 1; return 0; } @@ -404,17 +415,15 @@ static inline void check_skas3_ptrace_faultinfo(void) n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); if (n < 0) { - ptrace_faultinfo = 0; if (errno == EIO) non_fatal("not found\n"); else perror("not found"); - } + } else if (disable_ptrace_faultinfo) + non_fatal("found but disabled on command line\n"); else { - if (!ptrace_faultinfo) - non_fatal("found but disabled on command line\n"); - else - non_fatal("found\n"); + ptrace_faultinfo = 1; + non_fatal("found\n"); } stop_ptraced_child(pid, 1, 1); @@ -437,38 +446,30 @@ static inline void check_skas3_ptrace_ldt(void) if (n < 0) { if (errno == EIO) non_fatal("not found\n"); - else { + else perror("not found"); - } - ptrace_ldt = 0; - } + } else if (disable_ptrace_ldt) + non_fatal("found, but use is disabled\n"); else { - if (ptrace_ldt) - non_fatal("found\n"); - else - non_fatal("found, but use is disabled\n"); + ptrace_ldt = 1; + non_fatal("found\n"); } stop_ptraced_child(pid, 1, 1); -#else - /* PTRACE_LDT might be disabled via cmdline option. - * We want to override this, else we might use the stub - * without real need - */ - ptrace_ldt = 1; #endif } static inline void check_skas3_proc_mm(void) { non_fatal(" - /proc/mm..."); - if (access("/proc/mm", W_OK) < 0) { - proc_mm = 0; + if (access("/proc/mm", W_OK) < 0) perror("not found"); - } - else if (!proc_mm) + else if (disable_proc_mm) non_fatal("found but disabled on command line\n"); - else non_fatal("found\n"); + else { + proc_mm = 1; + non_fatal("found\n"); + } } void can_do_skas(void) -- cgit v1.2.3 From f1ef9167ca4494a8c6d71d0031c73e9c8841eadd Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Thu, 12 Jun 2008 15:21:41 -0700 Subject: uml: work around broken host PTRACE_SYSEMU Fedora broke PTRACE_SYSEMU again, and UML crashes as a result when it doesn't need to. This patch makes the PTRACE_SYSEMU check fail gracefully and makes UML fall back to PTRACE_SYSCALL. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/start_up.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) (limited to 'arch/um/os-Linux/start_up.c') diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c index b4b36e0f2e89..183db26d01bf 100644 --- a/arch/um/os-Linux/start_up.c +++ b/arch/um/os-Linux/start_up.c @@ -121,8 +121,10 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit) { int status, n, ret = 0; - if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) - fatal_perror("stop_ptraced_child : ptrace failed"); + if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) { + perror("stop_ptraced_child : ptrace failed"); + return -1; + } CATCH_EINTR(n = waitpid(pid, &status, 0)); if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) { int exit_with = WEXITSTATUS(status); @@ -212,7 +214,7 @@ static void __init check_sysemu(void) if (n < 0) fatal_perror("check_sysemu : wait failed"); if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) - fatal("check_sysemu : expected SIGTRAP, got status = %d", + fatal("check_sysemu : expected SIGTRAP, got status = %d\n", status); if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) @@ -254,9 +256,11 @@ static void __init check_sysemu(void) if (WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))) { - if (!count) - fatal("check_ptrace : SYSEMU_SINGLESTEP " - "doesn't singlestep"); + if (!count) { + non_fatal("check_ptrace : SYSEMU_SINGLESTEP " + "doesn't singlestep"); + goto fail; + } n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, os_getpid()); if (n < 0) @@ -266,9 +270,12 @@ static void __init check_sysemu(void) } else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) count++; - else - fatal("check_ptrace : expected SIGTRAP or " - "(SIGTRAP | 0x80), got status = %d", status); + else { + non_fatal("check_ptrace : expected SIGTRAP or " + "(SIGTRAP | 0x80), got status = %d\n", + status); + goto fail; + } } if (stop_ptraced_child(pid, 0, 0) < 0) goto fail_stopped; -- cgit v1.2.3