From 01bfa1fc30bd5715918c44a1b226d43c9491a0ae Mon Sep 17 00:00:00 2001 From: Luca Dariz Date: Sun, 3 Apr 2022 17:00:19 +0200 Subject: add separate port_size and mach_port_name_size definitions * cpu.sym: retrieve size of vm_offset_t and mach_port_name_t from gnumach headers at compile type. * global.{c,h}: add port size as a variable and initialize it to the port name size. * lexxer.l: apply port or port name size to the corresponding types, instead of using the word size. * parser.y: update port size if we're generating for kernel-space (server or client). Also re-initialize default port types to account for this change. * type.c: use port size instead of word size in default port types and runtime checks. There are many assumptions about mach_port_t: - on kernel side, its size is the same as a pointer. This allows to replace the port name with the address of the corresponding data structure during copyin in mach_msg() - in mig, this is also the "word size", which is derived from gnumach headers as the size of integer_t - its size is also the same as natural_t, so it's possible to model structures like mach_port_status_t as an array of integer_t in mig. This is convenient since arrays and structures can't have mixed types. - its size is always the same as the port name size This patch does not change the current behaviour on 32-bit kernels, but allows for some of these assumptions to be broken on 64-bit kernels. This is needed to have 32-bit port names on 64-bit kernels and be able to support a 32-bit userspace. It still leaves the choice for a 64-bit userspace, if all integer_t and natural_t are to be extended to 64 bit. However keeping 32-bit port names seems to be the right thing, based on previous discussions [1], even for a 64-bit kernel. The only assumption kept is that in kernel-space ports are always the size of a pointer, as they refer to a data structure and not to a specific port name. To ensure this is true for various user/kernel combinations, we dynamically change the port size if we're generating code for kernel-space server or clients, and keep the size of a port the same of a port name for user-space servers and clients. [1] https://lists.gnu.org/archive/html/bug-hurd/2012-04/msg00000.html Signed-off-by: Luca Dariz Message-Id: <20220403150020.120799-2-luca@orpolo.org> --- cpu.sym | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'cpu.sym') diff --git a/cpu.sym b/cpu.sym index fcf6241..5e34074 100644 --- a/cpu.sym +++ b/cpu.sym @@ -106,3 +106,7 @@ expr sizeof(double) sizeof_double expr sizeof(mach_msg_header_t) sizeof_mach_msg_header_t expr sizeof(mach_msg_type_long_t) sizeof_mach_msg_type_long_t expr sizeof(mach_msg_type_t) sizeof_mach_msg_type_t +expr sizeof(vm_offset_t) vm_offset_size +expr (sizeof(vm_offset_t)*8) vm_offset_size_in_bits +expr sizeof(mach_port_name_t) port_name_size +expr (sizeof(mach_port_name_t)*8) port_name_size_in_bits -- cgit v1.2.3