From 8c420b8d59e8e045aa733f478adb1d0509d447e3 Mon Sep 17 00:00:00 2001 From: Gary Benson Date: Wed, 25 Jun 2014 11:49:55 +0100 Subject: [PATCH] Merge ps_get_thread_area This commit adds a new helper, x86_linux_get_thread_area, to hold the common parts of the ps_get_thread_area functions in i386-linux-nat.c and amd64-linux-nat.c. gdb/ 2014-07-11 Gary Benson * amd64-linux-nat.c (x86_linux_get_thread_area): New function. (ps_get_thread_area): Delegate to the above in 32-bit mode. * i386-linux-nat.c (x86_linux_get_thread_area): New function. (ps_get_thread_area): Delegate to the above. --- gdb/ChangeLog | 7 +++++ gdb/amd64-linux-nat.c | 73 +++++++++++++++++++++++++++++++------------ gdb/i386-linux-nat.c | 36 ++++++++++++++++----- 3 files changed, 88 insertions(+), 28 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bbd61e2d98..d5f15ac924 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2014-07-11 Gary Benson + + * amd64-linux-nat.c (x86_linux_get_thread_area): New function. + (ps_get_thread_area): Delegate to the above in 32-bit mode. + * i386-linux-nat.c (x86_linux_get_thread_area): New function. + (ps_get_thread_area): Delegate to the above. + 2014-07-11 Gary Benson * amd64-linux-nat.c (amd64_linux_read_description): Renamed to diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c index c442878a4d..57e5c51a68 100644 --- a/gdb/amd64-linux-nat.c +++ b/gdb/amd64-linux-nat.c @@ -490,6 +490,47 @@ x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid) +/* Helper for ps_get_thread_area. Sets BASE_ADDR to a pointer to + the thread local storage (or its descriptor) and returns PS_OK + on success. Returns PS_ERR on failure. */ + +static ps_err_e +x86_linux_get_thread_area (pid_t pid, void *addr, unsigned int *base_addr) +{ + /* NOTE: cagney/2003-08-26: The definition of this buffer is found + in the kernel header . It, after padding, is 4 x + 4 byte integers in size: `entry_number', `base_addr', `limit', + and a bunch of status bits. + + The values returned by this ptrace call should be part of the + regcache buffer, and ps_get_thread_area should channel its + request through the regcache. That way remote targets could + provide the value using the remote protocol and not this direct + call. + + Is this function needed? I'm guessing that the `base' is the + address of a descriptor that libthread_db uses to find the + thread local address base that GDB needs. Perhaps that + descriptor is defined by the ABI. Anyway, given that + libthread_db calls this function without prompting (gdb + requesting tls base) I guess it needs info in there anyway. */ + unsigned int desc[4]; + + /* This code assumes that "int" is 32 bits and that + GET_THREAD_AREA returns no more than 4 int values. */ + gdb_assert (sizeof (int) == 4); + +#ifndef PTRACE_GET_THREAD_AREA +#define PTRACE_GET_THREAD_AREA 25 +#endif + + if (ptrace (PTRACE_GET_THREAD_AREA, pid, addr, &desc) < 0) + return PS_ERR; + + *base_addr = desc[1]; + return PS_OK; +} + /* This function is called by libthread_db as part of its handling of a request for a thread's local storage address. */ @@ -499,26 +540,18 @@ ps_get_thread_area (const struct ps_prochandle *ph, { if (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 32) { - /* The full structure is found in . The second - integer is the LDT's base_address and that is used to locate - the thread's local storage. See i386-linux-nat.c more - info. */ - unsigned int desc[4]; - - /* This code assumes that "int" is 32 bits and that - GET_THREAD_AREA returns no more than 4 int values. */ - gdb_assert (sizeof (int) == 4); -#ifndef PTRACE_GET_THREAD_AREA -#define PTRACE_GET_THREAD_AREA 25 -#endif - if (ptrace (PTRACE_GET_THREAD_AREA, - lwpid, (void *) (long) idx, (unsigned long) &desc) < 0) - return PS_ERR; - - /* Extend the value to 64 bits. Here it's assumed that a "long" - and a "void *" are the same. */ - (*base) = (void *) (long) desc[1]; - return PS_OK; + unsigned int base_addr; + ps_err_e result; + + result = x86_linux_get_thread_area (lwpid, (void *) (long) idx, + &base_addr); + if (result == PS_OK) + { + /* Extend the value to 64 bits. Here it's assumed that + a "long" and a "void *" are the same. */ + (*base) = (void *) (long) base_addr; + } + return result; } else { diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c index 62ad29fb41..d647c3d5b0 100644 --- a/gdb/i386-linux-nat.c +++ b/gdb/i386-linux-nat.c @@ -848,12 +848,12 @@ x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid) -/* Called by libthread_db. Returns a pointer to the thread local - storage (or its descriptor). */ +/* Helper for ps_get_thread_area. Sets BASE_ADDR to a pointer to + the thread local storage (or its descriptor) and returns PS_OK + on success. Returns PS_ERR on failure. */ -ps_err_e -ps_get_thread_area (const struct ps_prochandle *ph, - lwpid_t lwpid, int idx, void **base) +static ps_err_e +x86_linux_get_thread_area (pid_t pid, void *addr, unsigned int *base_addr) { /* NOTE: cagney/2003-08-26: The definition of this buffer is found in the kernel header . It, after padding, is 4 x @@ -873,19 +873,39 @@ ps_get_thread_area (const struct ps_prochandle *ph, libthread_db calls this function without prompting (gdb requesting tls base) I guess it needs info in there anyway. */ unsigned int desc[4]; + + /* This code assumes that "int" is 32 bits and that + GET_THREAD_AREA returns no more than 4 int values. */ gdb_assert (sizeof (int) == 4); #ifndef PTRACE_GET_THREAD_AREA #define PTRACE_GET_THREAD_AREA 25 #endif - if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, - (void *) idx, (unsigned long) &desc) < 0) + if (ptrace (PTRACE_GET_THREAD_AREA, pid, addr, &desc) < 0) return PS_ERR; - *(int *)base = desc[1]; + *base_addr = desc[1]; return PS_OK; } + +/* Called by libthread_db. Returns a pointer to the thread local + storage (or its descriptor). */ + +ps_err_e +ps_get_thread_area (const struct ps_prochandle *ph, + lwpid_t lwpid, int idx, void **base) +{ + unsigned int base_addr; + ps_err_e result; + + result = x86_linux_get_thread_area (lwpid, (void *) idx, &base_addr); + + if (result == PS_OK) + *(int *) base = base_addr; + + return result; +} /* The instruction for a GNU/Linux system call is: -- 2.34.1